This sounds absolutely horrible! You are so brave and strong for dealing with this this far. Honestly, I think you should confront her, and tell her what you think. Maybe something like, "Name, I know we're friends but I can't keep doing this. It is not normal. I really hate this, and I don't want to do this anymore. Please stop." If you don't want to do that, tell someone. If you don't tell someone something is going to go really wrong. I know I sound like an adult lecturing a little kid, but you should really tell someone. They can watch her and make sure she doesn't kill herself. I suggest after that, if she doesn't get better, just cut ties with her. This seems really dangerous and horrible. I'm sorry that I'm not giving very good advice since I'm not good at this stuff, but I really want to find some way to help since you seem to be in a horrible situation.

Listen to me, when she says she's going to kill herself it's a way of bullying. An empty threat. Don't listen to her. Stop cutting yourself, please. Tell someone, ANYONE, it's for the best. Your parents, a counselor... the police. Please, tell someone, it's the right thing to do.

GO TO SOMEONE

anyone. a guidance counselor! someone at school!

AND PLEASE STOP