Of course one of the sinister explanations may be true, but it's common for relationships to start intense and rapidly fall apart, regardless of who is involved. During the initial infatuation stage, we tend to imagine that lots of things we don't know about the other person are all wonderful (or we just don't think about them), and the infatuation can end quickly when we discover that some of what we imagined was far from the truth. So this perfectly ordinary thing may have happened here; she may have noticed something about you that made you seem less her type than she'd imagined before.
