The absolute worst thing to do in a situation like this is stay. These kinds of people rarely acknowledge your own problems, nor have an inclination of changing to help themselves.
I was in a stuffty relationship with a chick that was in therapy for "depression", constantly cut herself, got drunk frequently, broke into schools, cheated on me and overall was extremely pathetic. Just like you, I had to stop a bunch of her Self Delete attempts. Aside from the fact this was attention seeking on a whole new level, she also had a habit of forcefully ignoring my own problems and issues and instead wanted everything to be about her. I feel like your situation is somewhat similar.
The best thing you can do right now is cut it off. If you prolong this thing, she's going to get worse, and it's going to be harder for you to say no. Do it respectfully, in person, but do not just sit and wait for the "right" moment. You deserve better, and hopefully she's mature once she understands why her persona led to the breakup, if she ever does.
And as Dannu said, don't be manipulated by guilt trips. These kinds of people like to twist everything to fit their design even when it's not going to work out in the long run. Also, can confirm as Dooble said; my ex didn't off herself when we broke up. Sure, she was became more pathetic, but she's still trucking along.
