What's the deal with this guy I like?

So there's this guy I hooked up with a few months back. We're now in a cl together and I party with his frat a lot. I talk to him in cl and everything's fine...I even think I'm starting to like him now. Well I saw him at a party last night and talked to him pretty much the whole night. He then invited me to go get food with him and a few friends. I was drunk so not in my right state. Well he left where we were eating without me and this other guy. We go back to the frat house and I didn't see him again for the rest of the night. I was so confused and kind of angry because we're always flirting. We were sitting in the car together and he was rubbing my back and leg so I thought something was going to happen. I don't know if he just left because he was drunk and being stupid or what the deal is. I really have started to like him and I'm attracted to him. Should I fb and just joke about he left me? I feel like I may be sending mixed signals and I don't know if it's turning him off. I'm also kind of flirty with other guys when I'm drunk.. :/ I would really appreciate some help with this situation!