I was in a similar situation and tried explaining my feelings to my friend who got mad and ignored them. so we stopped talking, it's been weeks now and even though I'm still struggling its better without having to deal with her issues too. I see her statuses on fb basically saying she's going to kill herself and it makes me mad and even though I want to hell her I realise/remember the reasons why I stopped talking to her.

so I think you need to put yourself first. you can't help her if your not okay.