something very similar happened to me a few months back. I met this girl that i was introduced to by my salsa instructor. We hit it off that night, we danced, had a great time....to the point where my salsa instructor saw me later that night and said "my friend really likes you". we exchanged numbers that night, we went out 2 days later, had a great time....kissed after 1st date. The next week or so she appears to get a little flakey, then as i backed off, she texted me and offered second date. We had a great time on second date, again ended with a kiss. Then she got a little distant, i did not chase at all, just sat back. She then reached out and said she may go to the dance place (same place we met) that night, i told her i would save her dance and she replied with a smiley face. And that was the last i heard from her...this was back in august. She sent me a FB post for my bday in october, but i did nothing about it.
Bottom line is i can not point to anywhere in the time that i met her that i did anything wrong. i have no explanation for her distance except the fact that she is very very pretty and maybe was trying to get me to chase her....but if that was her plan, it back fired because I never did, however i did show her i was interested. But i have enough self respect to never chase anybody.
So like you bro, i have no idea what happened. Especially since the last time i heard from her she was planning on meeting me. it is what it is...yes it sucks. I honestly still think about her, although i would get killed on here for admitting it, i do still think about her. But have remained strong and have done NOTHING. We'll see if she reaches out ever again, i doubt she will. But there is not much i can do.