Why did he do this? i need to know!?

well me and this guy have talked 2 on msn, our convos last about 2 hours, any way we talk sometimes in school too, but yesterday i said heyy ,then the whole process of sup and everything, then he said i have to go talk to you tomorrow, our convo lasted bout 5 mins. then today i said hey, then he did int respond, and when i checked his name, it was busy!