OK so here's a lengthy post because I feel like we've experienced the same life, just a decade apart. I'm going to put in some personal experiences from myself, so you can relate or not. I just feel like you're opening up so I should as well.
TL;DR Set simple goals and achieve them, then move up from there.
OK so from what it sounds like, you are either just developing depression. Or since you had trauma at a young age it might be severe depression finally breaking you. I had a few traumatic experiences starting at age 5 till I was about 19. But I didn't lose a family member like you have. So I'm not going to pretend what effect that had on you, but mine were near death experiences so I would "group" them in the same level of mental trauma. Also another difference is that I started my drug abuse later than you did, but for about the same amount of time, from 18 to 25. I did the same thing you did with trying pretty much everything I could, I ended up on herion for 2 years. Also in case you didn't already realize it, you are an addict and always will be. There's nothing you can really do about that. But don't think of it as a bad thing, there's always a silver lining to everything.
You definitely need to be on working medication. If it doesn't do what they say it will do after 2 months, usually an adequate amount of time to actually notice differences, tell the doc you want to try something else. There's a thousand different meds for everything. The docs only knows what you tell them so make sure you be completely truthful (unless you killed someone then change the story so it doesn't sound like you did lol). Also here's a two birds one stone scenario that can help you: ask if there's any groups you can go to. I used to go to a dual diagnosis meeting every Thursday. Dual diagnosis means mental disorder coupled with previous serious drug or alcohol abuse. It's great because you hear people stories and can relate so you stop feeling like an alien. Also this let's you meet new people and allows you to socialize. And since everyone there has a disorder they won't judge you. There's always those ones that'll judge, but they usually don't last more than one or two meetings anyways.
Also now that I think about it, I hope I'm not making you feel bad by assuming and labeling you. But personally for me, once I found "my label" it helped me kick start my recovery. Mentally and drug abuse. It's not going to be a quick fix either. Most people that go to therapy continue to for years. If you are worried about cost, you are in a TAY (transitional age youth) bracket. There are loads of TAY programs that will help with therapy, education, jobs, and just places to hang out. I highly recommend checking into this. They usually run about 37$ a year so it's basically free.
As far as your utter lack of motivation goes, you need goals. You are going to college and you work out which means you at least have will power, which is great. But you need to set yourself monthly and yearly goals. They don't have to be big, but they need to be there. It keeps you focused on growing. They can be easy things like "I'm going to volunteer 5 hours at _____ this month". Video games are great, but only if you literally want to waste time. They achieve nothing but possible carpurtunnel later in life. Start taking an hour or so every time you decide to play games with learning something new online. Then play. Eventually you may find yourself not even wanting to play afterwards. I no longer play games. But thats me and not you, everyone enjoys different things. The point is to not make your life repetitive, depression and repetition do not mix well.
In closing, you are not broken. You were given your deck of cards in life and played them differently than most others. I mean you didn't get into the whole cutting/suicide crowd when your mom died. If you had, I might not be giving you this advice today. A vast majority of youths that I've consoled tend to go that way with the loss of parents. If you take anything from this, then please remember: as far as anyone knows without doubt is that no one knows where life will end, it's up to you to try to change it the way you want it.
Also kudos on taking the time to open up to complete strangers. I noticed your drugs post is two weeks old, so I'm afraid you aren't getting the advice you want. I hope this helps because I feel like I've been in your exact shoes just few years ago. I'm still getting my life on track after two years. It's a long road, but definitely one less traveled and you'll be wiser for it in the end.
Any other questions, feel free to pm me anytime :) If I can help it, I try to turn sad people into happy people.