if there's one thing I learned about girls dude, if she's interested you'll know. if you feel like she's not that into you then don't waste your time dude. the fact that it happened at a club makes it even worse. she probably just wanted someone to make out w/ that night and it happened to be you.
You know what, there's so much negative stuff on this, it's nice to see some good stuff occationally.
Big congratulations to you and your girlfriend, I'm happy that you made it work despite the distance. Especially as a person who is in the same position as you were 5 years ago, it gives me hope despite my social anxiety.