It's really tough to be blindsided by a friend like that. I wonder if she was ever as good a friend to you as you were to her. Have you always been the one that has to smooth things over? She sounds like she has an abusive streak that gets worse when she doesn't get her way. If you feel like you should do something, than email her and keep it simple. You may need to take a break from her - she's obviously going through something that has nothing to do with you...and you don't need to be her doormat.