Tell the truth?

I think you should be honest with her, but only one situation at a time. Don't blow up on her and let everything loose at one time. That will just overwhelm her, and you are most likely going to get a more explosive reaction. When she starts her crap, tell her the truth. Tell her she is overreacting and to calm down. Don't hold back, you aren't doing her any favors. My best friend and I have been friends for 23 years. (since kindergarten) The one thing I truly love and respect about her is that she NEVER holds back. She tells me exactly what she thinks and how she sees it no matter what I want to hear. I love her for that. She's the one person I can always count on, and the one person that will never let me down. Maybe it's time to change your role in her life, or just slowly let her go.