As someone who knows the disorder, I would ask yourself, how you would have wanted to be treated at your lowest low?

I am hard to deal with and know I've but stress on just about every relationship in my life. If I sensed a friend pulling away, it would probably make me more clingy, with less boundries and intesify my crazy. Maybe that explains some of her current state?

Having the conversation with her may help, letting her know exactly what behaviors are no longer tolerable and setting boundaries for both of you. Essentially what flooded said- be honest, firm, don't debate!

Good luck!