We hooked up...now what?

So I really like this guy. He liked me first, and I kinda fell for him. We were in one class together, and we started talking and texting. We never went more than 2 days without talking. I'm going to be a senior in high school (age 17) and he's going to be a college freshman (age 19). He has kind of a demanding job, and whenever we would try to get together, something would happen. (Called in to work, sister took the car, etc.) It became a bit of a running joke. But finally we did get to go on a date, and yes we hooked up (made out). So today he texts me (inside joke/flirty) , a good sign, and I texted him back about 15 minutes later. Now it has been about 5 1/2 hours, and he hasn't texted me back. What's going on? What should I do? I just sent him a normal message back...not like i was disinterested.