I'm sorry you are going through so much pain right now. I had to reply because I went through a similar situation when I was growing up with my Mom. I am in my 40's now. My mom seemed to hate me most of my teen years for some reason. Actually she didn't start to show her love for me until I moved away, then she couldn't hear from me or see me enough. She was mentally ill and I now realize that and I realize there was nothing I did wrong. So I'm saying to you that you are not doing anything wrong. Your mom is ill just like you said. I was suicidal through my teen years and therapy helped me not to do it. There are clinics that do not charge you if you can't afford to pay. Hospitals have them, or local mental health agencies. Look on the internet for mental health services in your area and make calls until you find someone who will help you. Talking to someone will help. Don't try to reason with your Mom or argue with her because she is not rational and it will do no good. Just avoid her if you can. If she starts to argue just let her and don't say anything back. It's hard and I know it is but you can get through this because I did. Do you have family or friends that you can visit sometimes? Try to reach out to others so that you don't feel so alone. I am praying for you.
Also, I want to recommend 2 books for you to read. "When you and your mother can't be friends", by Victoria Secunda and "Toxic Parents", by Susan Forward. Those are very good books that I have read. Make sure you keep them somewhere where she won't see them, you don't need that. My Mom is gone now and like I said she always wanted me around once I moved and wasn't around anymore. I don't know why Parents act the way they do, some parents don't know how to show love or compassion. Some parents are too needy themselves. I finally after I was older just accepted that she was ill and I tried to have a better relationship with her. It still was difficult and I never forgot those painful years. Reading your post made me sad and made me remember those times but having been there myself I know you can get through it. So hang in there and look for help and reach out to others.

BreeMarie