It's very difficult for me to judge the situation properly, as I only have what's in this thread to work with, but if I may say so (please don't take offence) it sounds like you might be overreacting a little bit.
When you find yourself attracted to a girl in both body and mind, it can be very difficult to process emotions, and I think it's possible that you might be letting that cloud your judgement. If, as you said, her excuses were innocent and legitimate, and she was apologetic for screwing you around, then perhaps you should consider that she really did just become a little overwhelmed by factors outside of her control.
The question I would ask myself is, if this happened with a male frend of mine, would I jump to conclusions, or just assume the excuses he gave were the truth?
Once again, I could be wrong because I only have limited information to work from, but it seems to me that perhaps it's not quite the end of the world yet.