What do you do when your mother is an insane meth abuser?

I am 36 years old and my mother is 100% addicted meth- amphetamines. My whole life I have never seen her without being on some kind of drug. Now that she is 50+ years old she has lost what little mind that she had. She is paranoid, delusional, massively depressed and violent. She refuses to get any help because she thinks everyone is trying to rape and kill her. I want to help her but I cant. I don’t have the money to get her any real treatment not to mention she has already said that she would just check herself out in 3 days. Do I just walk away and let her die? I know that I cant be around her anymore because I have a problem with depression myself. Any ideas???