How could my best friend betray me this way?

[Longwaytogo]

We've been friends for 3 years and i thought she was a good friend. She was always there when I needed to talk and was a shoulder to cry on. All my other friends let me down. When I got sick, she'd always call and check up on me. She often had me over and cooked my favourite food. I was even close to her boyfriend who's a good guy. My bf dumped me over the weekend - my 2nd breakup in 2 years. Of course, I called her to tell her.
At 1st, she was understand then she offered to give me constructive criticism. The thing is, it wasn't constructive. She just went on about how I'm too negative and I like to play the victim. I snapped and told her I don't want to be friends with her anymore. She got mad and accused me of punishing her for being honest. She dragged me down when I'm brokenhearted, what a horrible person! I removed her and her boyfriend from my Facebook. How could she do this to me? How dare she criticize me like that?