I'm not going to look after my severely depressed friend
Why wouldn't you help out your depressed friend?
I think she is starting to act crazy and not listen to me anymore.
She's your friend, so it's bad not to help them when they are in need of it. Wouldn't you want help from your friends if you were feeling depressed?
Nah, I have better shit to do and I'm not going to help her.
You shouldn't have to do it alone have you talked with her about seeking professional help? I get that dealing with mentally ill people can be really tiring, but it sounds like she really needs a friend right now.