(((((snowflake))))) I reccomend telling her about your concern for her, and asking her to promise you she won't do it. If she promises, she probably won't do it. For some reason, this is one of those things that people tend to keep their word on. If she won't promise, I reccomend very strongly that you get her some help immediately. However you can.

Aside from that, I think you are doing all you really can do right now. Keep being there for her to talk to, because you can help relieve her pain- even if just a little, it will make a difference. But also take care of yourself. You need to be strong and healthy for you AND for her, or you won't be able to help either one of you.

So sorry you are going through this. I can't imagine how worried and heartbroken I would be if I were in your shoes.