How would child custody work for my situation?

I am 16 and I have a mother who constantly says she hates me and she does not want to see me. She has also told me to go to hell and never come back before. I try really hard in school and I am an rising Senior. Nothing is ever good enough for her, though. I didn't get any A's on my report card for my last semester of my Junior year because, I had very hard classes. They were high B's, though. She called me dumb among other things. I try so hard to please her, but nothing is good enough. I spend most of my time in my room just so I don't have to deal with her calling me names and telling me she hates me; things like that. The only time I leave is to just leave the house completely or eat/use the bathroom. Somehow I cause a lot of trouble not bothering anyone. Although she has told me she hates me and she never wants to see me again, she has said that I would ever be able to leave her is if someone else gained custody of me. I have a grandmother who lives here in the same house, so it would be pointless for her to get custody of me. I would love if she could buy a house and we could move away with my little brother in that house. I don't have much contact with much of my other family, in fact, most of my other family is alcoholics. The only alternative I have is to live with my best friend and her family. Her mom has always been like another mother to me and I am just wondering how would custody would work for my situation. I have looked into it and I've only found child custody info for divorced parents and custody going to family members.