I have completely been in your spot and understand how you feel. When I felt this way, it was the result of over 22 years of constant suffering that I had tried to cover up, ignore, and repress. Finally, something happened that set it all off - I became more depressed than I had ever been in my life, felt extremely isolated, all of a sudden became incredibly socially awkward (way beyond my personality), and didn't want to live. What I'm about to say might be a little controversial, so please think deeply about it.
There was a week where I actually wanted to no longer live. I'd had suicidal thoughts my whole life - I remember I used to get tormented by these kids on my bus every day in 7th grade and I would come home, open my pocket knife, put it to my wrist, but not go any further. I knew that I didn't want to die. I had dealt with rejection and said that I didn't want to be alive; I knew deep down it was a lie. This time was different, I woke up every single day wishing that I could just go back to sleep and it would all be gone. I knew how I'd kill myself painlessly, I just a) couldn't quite arrange the time and b) couldn't do it to my mother. If she hadn't been around, it would have happened.
Before I say how it played out for me, I do believe that the ultimate answer is in mindfulness and meditation; however, there's no way that when I was in the place that I'm talking about that I would have had enough faith in it to give it a real chance.
When I was in this place I was smoking a lot of cannabis and drinking a lot to take away my pain (not to mention, compulsively eating junk food, viewing pornography and masturbating, playing video games and smoking cigarettes). The weed and alcohol weren't strong after a while so I'd wanted to throw something else into the mix - luckily (?), where I'd lived didn't have the sorts of drugs that I was looking for (cocaine or psychedelics, just painkillers and heroin which I hated) so I asked my mom to take my to a psychiatrist; I knew she'd say yes because she knew I was in a lot of pain. I still had the stigma about actually getting psychological help, but I was in so much pain that even though I couldn't accept that I needed it, I went to a psychiatrist hoping to get some Xanax, I'll be honest. Please keep in mind that I'm not condoning drug-seeking behavior, I'm just telling my story.
I didn't really know much about the field or the practice, and it turns out that I was sent to a therapist who couldn't give me drugs. The reason that I'd felt the way I did was because of what I'd felt my father had done to me; my mom still got him to pay for it at $125 a visit, so I decided to keep going just to hurt him in any way that I could. She referred me to a psychiatrist who prescribed me anti-depressants and anti-anxiety pills. I got part of what I'd wanted, extra drugs were just a bonus. I didn't think that anti-depressants had any merit, but I really cared less about what I put in my body and just wanted to be high so I took them too.
The first day that I took them (per instruction, not having done anything else) I went to work and I was high as a kite. It was a different kind of high though because I wasn't impaired. I was super productive and had a good day there. I was still extremely depressed and had many underlying issues. I still do, but I can't begin to say how much better I am than I was in when I was in the place that I get the impression that you might be in right now.
Over time, the artificial up that the antidepressants gave me was a boost that helped me set aside my problems and attack the roots of them. I think that this is where they get their bad rep from; you can't take them and think that it's all going to be better - it's only a temporary solution. For me, taking them as a means to put aside my issues and make a happy life in the meantime by acting diligently and looking deeply was the segue that I needed to get out of the place that I was in.
During this time, I started reading a lot. If you're in a place to read, then I highly recommend "Learned Optimism" by Martin Seligman. This book has had the single biggest positive effect on my life of any book.
I'll be honest, I still have a lot going on that I'm working on and it's getting better, why else would I be here? However, I haven't felt like I haven't wanted to live in almost 3 years and don't think that I could return to that place ever again. Feel free to message me if you would like to talk any more, I'd be glad to listen.