Your not wrong.
It totally sucks.
Espiacally for the fact that she picked him over you after missing
your birthday.
It can make anybody want to cry forever and feel let down.
Here's what you should do, next time you see her or so talk to her, let her know how you felt about what she did and dont feel wrong in anyway.
I'm sorry that you felt like that. It really hurts when some one does these kind of things like walking all over you.