Search Results: going down on eachother

We met when he visited my Student house with my flat mate, and we instantly hit if off!
We all went to a house party that night and me and him spent the whole time there in a separate room getting to know each other.
He asked for my number and text me an hour after we left the party, we were texting for a couple of days, every day him asking me what I was up to that evening however never initiated asked to do something and eventually the texting started dieing down so I asked! and he said he'd love to and suggested drinks the next evening.
So we met in a local pub and really hit it off, spent 4 hours just sitting talking and we suggested the possibility of heading to his for a movie as the pub was closing (12am) however he had lectures at 9 the next morning so i said I didn't want to be the reason for him to be missing lectures, so when saying goodbye he said we could do it another time along with going for a trip to a beach he wanted to show me and ghost hunting! (Things we wanted to show eachother) and then he (passionately) kissed me goodbye.
The next morning he text me checking that I got home safe and I replied saying yes and asked whether he made it to his 9am lecture, however he hasn't replied and it's been almost 4 days now. He mentioned on the date that he has lectures every day along with taking part in 4 different societies, so I understood he was busy, but still.. Any possible reasons why?