In all fairness its probably one of the following scenerios:
1) Wanted to get some attention but had fallen for the other guy (a true interest)
2) You may have done something irregular or odd which pushed her away
3) May have come off as inexperienced
I'm not implying that you're 1,2,3, in my experience it usually was these 3. Don't sweat it, everyone ****s up and it only makes you better and more aware of your actions and the actions of others. Learn from them and don't blow them off.
I remember when I was really young I dated these hot chick for about 2 weeks. She was really into me, and she brought me to a golf park and made out heavily for 20min, then the evening was called. The next day she called and said I dont think were meant for each other, etc... Turns out I was a really lousy kisser. So I said **** me, I'm going to get this **** down. I popped out tons of books, read through tons of forums and tips, and began practicing with my new gf. Sure enough, it paided off.

But I won't lie, being told that rips you apart.