Same thing happened to me, about a year ago - not my first love, but I still had not been in a relationship up until that point. She did not mind playing games with my mind either. Honesty was probably a foreign concept to her.
The trick is not to pay any attention to her. Stop obsessing about her. There is no need to find out why she is as she is, and why she behaved as she behaved. These questions are best left to professional writers. Your life goes on. And will get better. At least mine did
