I wasn't going to add to this thread 'cause it seems everything's been said but hey, here goes anyway. Though I doubt I'd've actually gone and given her whichever degree you gave her, I would've felt exactly the same. I take some pride in treating people with the basic amount of respect and when I find myself being denied that same thing, I go nuts. If I understand you correctly, you'd've been okay with it all had she apoligised in a manner proportionate to the wrong she'd caused you. But she didn't, did she? She minimized the situation and made you feel like you were overreacting, which you weren't given the circumstances. You were doubly betrayed, once by being forgotten and the other by being denied proper reparation. That is very indicative of the kind of person she is. Ditch the bitch.
CQFD.