I think that your feelings are completely understandable. I would be ticked off if my friends left me out in the cold too. I don't know what to make of the spring break incident. That could have been a miscommunication - she didn't hear you or something - but calling you a liar is pretty uncalled for, and that would tick me off too. I don't know what you should do about this, particularly.

I do agree with you that you've been treated badly here. I would say something about it, personally. They were being jerks. I wouldn't transfer schools over just that, however, just because that is such a major decision and I'm sure you could find new friends at your current school.