You are so incredibly close to getting away from your crappy living situation, not only that... but things often change dramatically with no rhyme or reason. I went through various stages where I had a lot of friends that were primarily outcasts, but then I got into an advanced charter school where I spent half of my day and didn't seem to fit in with them anymore. I had almost no friends from my high school, but enjoyed acquaintances at the charter school more. They mostly had their own friends at their schools though, so I spent a lot of my time on my own.
Something happened around junior year where I started becoming more popular, yet I was still incredibly shy so I didn't really get that I was until after H.S. ended. Hell, I'm 36 now and just found out one of the popular guys in school apparently tried to hit on me all the time, but I never realized it... I just thought he was being nice, lol.
My advice would be to really focus on getting to college, will your dad at least help you with that? Regardless, whether you think you'd be good at it or not, I think you should look into programming... if you end up having a knack for it you can offer yourself a lot of financial freedom to break away from unhealthy family members and get the medical care you need. It's tough out there, even for those of us who graduated from the best universities.
Just know that most people have shit that they don't talk about, because our lives have become this competition in showing each other who has the best happy pictures... not who actually has a happy life. Most people I went to college with have no idea how bad my situation is... we all went to a top ten university. But, you know what? In last few months I have had several colleagues tried to sell my products quietly in FB messages. But we all manage to continue on for the good days, that's just life and most of us waiver between really good and really shitty times. When at your lowest, it's bound to get better again... the time it takes you to get out of your situation right now might seem like eternity, but I guarantee there will be a day when it seems like barely a passing moment in your memory and you'll wonder where the last five years went lol.