Girl vanished from the face of the Earth...

There was this girl I've been on a few dates with, we really clicked. We had a lot in common and I thoouughttt she was really interested in me. It just felt really.. surreal and perfect. (Of course I'm new to relationships, haha). I legitimately have never felt this way about anyone before. Our last date this happened. We had texted a week or so after that.. and randomly.. she stopped. She then came out on facebook, when she previously didn't have an "Interested in" section. I sent her a message to comment on it and never got a response there either.

I'm really heartbroken. I have no idea what I did wrong, or why she stopped talked to me. I swear she was acting like she really liked me. I just feel like crying everything I think about her, which ends up happening a lot. Rationally it's her loss if she just wants to cut off all contact like that, but I just really want her to come back to me. How do you guys deal with something like this?