What you're saying remind me of a book, from a French novelist : Jean Giono's, Un roi sans divertissement (roughly, it translates as : A king with no entertainment). The Wikipedia page about Giono tells us about one of the issues tackled in the book : a cop's realisation that he can be as evil as the murderer he's chasing. But that's not quite all, since the cop [SPOILER ALERT : (but you don't really read that book for its ending)] ends up committing suicide, even if he's pictured in the book as someone who have had everything he could need from life (yet, it's not ever clearly stated this way).
I have my own way of seeing this : his meaning in life was to chase bad guys. When he finally realised that to get his last one, he had to employ methods as bad as what the criminal would have done, the meaning disappeared. This book helped me thinking about this particular issue which is : the place of meaning in our lives.
Some other things helped me : In my first year of sociology class (in college), a professor once told us that in our occidentals societies, we have three "major steps", capable of creating huge traumatisms : school, work and long term romantic relationships. As a matter of fact, but that's a personal thought, they are the things supposed to structure an occidental human life (even if I'd personally add "family" to that set). And by "structure", I mean : give meaning to. This is all theoretical, but it somehow helped me realize that these steps were sometimes unwanted, almost mandatory for anyone in our societies AND massively impacting our lives. In other words : you can't find more important matter to discuss.
The second thing, or things, that helped me wrapping my head around this issue was a year I had to spend when I was 18 without any internet connexion (And then it happened again twice, for a duration of a month each). I'm 26, cellphones existed when I was 18, but I had none by choice. I also had no watch. I never lived a year like this one again. I had nothing else to do at my place than sleeping, watching movies, drawing or reading (I couldn't cook in here). Things that I enjoy doing but never felt like I could do it all day long. Nothing near video games. I have to spend months on a good, addictive video game, 8 hours a day, to feel like I have finally have had enough of it. And because I had no internet and no money that year, I didn't have any access to that kind of video game. It started as a boring year, but something funny happened. First, since I had nothing that I was thriving to do, I spent a lot of time in my head. Thinking about what I read last evening, what I was going to put in the next chapter of the novel I was writing, how to handle some of my relationships and I do not recall having been stressed a single time. I had all the time I could ask for. Highschool buildings were not far from my home, but I walked so slowly to get there every morning that it often took me more than 30 minutes (walking as a normal person in a capital city today, I guess it would take you 5 to 10 minutes). I have also never been so aware about the world around me and I hardly spent a day without being amazed by something I saw in the street (lights, trees, clouds, water, insect, you got the idea). It really was peaceful year.
The third thing is a year I spent at my parent's house, learning how to develop web applications and developing one by myself (it has been followed by two years of college and I am now a full stack developer). But during this year, I wrote code between 7 and 12 hours a day. Not because I had to, just because I wanted to. I had no boundaries, no one giving me orders, no deadlines. It was completely stress free and I enjoyed trying to solve problems the right way and learning things. Today I cannot imagine spending 12 hours coding and I am currently trying to keep the feeling of disgust about coding away.
The forth one is an idea my father was obsessed with. It is called "resilience". In short, for a human being, it is the capacity to resist stress. In other words : its capacity to adapt to its mutating environment. My father talked to me a lot about that idea and how guys in a jail could do all right if they were resilient enough. I thought this could be a real good quality to ask for, if I ever got 3 wishes. basically, you can find peace everywhere if you're resilient enough. And then a question started haunting me : how do one becomes resilient ?
The fifth thing is more of a personal theory, which fed on years of thinking and all the above. It could be summarised this way : 1) You got nothing in your life that is more important than your time. Things in which you invests it matter. Even if you think your job doesn't matter to you, spending 8 hours/day doing it + 1 to 2 hours of transportation has an impact on you. 2) These things in which you invests you time give you some feedback. The positivity, neutrality or negativity of these feedbacks are directly related to you personal values (in the broad sense of the word, a value can be something you have crystallized a long time ago, this part of the theory goes more in the field of psychology). A feedback can be a "good job" from your boss, you seeing a tool you spent months designing not being used at all by those who asked for it or even the amount of reddit reading you have done in your day. The "charge" (positive, negative or neurtal) of these feedbacks will depend of your current values. That "good job" could be taken as a huge reward of as a patronizing attempt. The amount of reddit reading will sound like a waste of time for someone hopping to make the difference at his job everyday. It will be great for someone really curious about a lot of stuff and just loving reading about them on reddit.
And we're here, and that moment, where I tell myself : now that you got it, find a way to get good feedbacks at what you're spending your day (that's the hard part). I'm currently on a good lead though. Basically, this is a basic philosophy problem : do I have to change my environment or do I have to change my way of interacting with it ? Since I tried changing my environment a few time, I took a shot at changing my way of interacting with it. And by interacting I do not mean the way I am modifying it, but the way I am perceiving it.
A month ago, I tried to make my time at my workplace a bit more meaningful, by getting rid of some highly addictive video game in my life. That way, when I'm at my job, I don't have somewhere I would rather be than here. Compared to that "peaceful year" I was describing, this was the most outstanding thing I could find. Having "something I'd rather do than being here" really prevents you from having ANY positive feedback from what you're doing. Whatever you do, you see, someone says to you, you'd rather be somewhere else. So, everything sucks. And at the end of the day, when you get your 1 or 2 hours of playing, that can't be enough. This part may sound a bit like I'm addict to some video game, that's not the case. It was not awful. My girlfriend didn't want to leave me, I still went out with my friends, etc. But during my work hours I still rather played than be here. Doing this, I changed the perception of my time. I felt like I had more free time. That I could do whatever I wanted again. Writing half an hour, then reading, than drawing, then cooking. All in one evening. And since I didn't want to be playing rather than doing my chores, doing them while talking with my girlfriend lightened these.
Secondly, I tried to re-define what was my own perception of myself in my current environment. I have never seen myself as a developer. For someone doing it 8 hours/day, it's a shame. It prevented my from getting any self-given feedback. These times when you see yourself that what you did today was some good work (from the standards of your peer that have became your standards, thanks for years of studying and, in my case, hard internet crawling). But also these times when you are absolutely aware that you have done some heavy pile of shit, but that you can do better. And that you will prove it tomorrow. These are good feedbacks too (at least, they're neutral, since you still have done some shit today). Anyway, defining yourself as someone doing what you do is important. For the society you're living in and for yourself. After doing that (well, I'm still doing it, but It more or less has had some direct effects), I started picturing me for real in some long term project (a PhD). Which I wasn't so sure about before.
Finally, I stumbled on one of my girlfriend's meditation book and started reading it. As much as I hated reading about all that "you are a wonderful human being" stuff, I had to admit that the "mindfulness" they were talking about really got to me. Being in the moment, not wanting to be anywhere else. Just getting what you can get from THAT moment. You're there anyway, so no need to make a problem out of it. And if you already feel there is a problem, better find out what it is. Are you anxious ? Angry ? About what ? What is stressing you, and can its source be removed ? That kind of thing... I'm currently reading it, haven't done much personal experiences about what they're teaching. Except for this year of peace. So I'm trying to remove most of the negative feedbacks and find some way to get good feedbacks instead.
Since I started this by writing about meaning in life, I will conclude with the same idea. Meaning is not built in some activities. It's built in every one of us. Of course, some pieces of that meaning are wired so deep inside us that it would take a lifetime to change them. But we are usually aware of these personal values. The trick is in not thinking that "it will be better somewhere else" and starting to realize what we have right here and building on it.
Sorry for the long post, and I hope I'm understandable, since English is not my mother language and all.