- Is the short answer
Thing with meeting at our ages is there are so many changes going on in our life, and so much prospect, it all depends where people are focused, but what us who are more love focused have to remember, we mustn't get in the way of the more... life focused people...
It does sound like conversation is running a little thin on the ground however, you can either sit back and just trust him, keep yourself busy, and hope he gets un-busy soon
Or finish it with him and be single...
My girlfriends a busy busy person planning to go to a top university and all she also has a job and so has a pretty packed life, thing to do is to try and pack your life like them, rather than sitting around waiting to hear from them
That way your both too busy to talk, and then when you DO have free time it'll be all the more worth it!
However not hearing from him since Monday is quite bad to be honest, but then again, I do know people who used to live literally 3 houses down from each other, were in an very strong relationship, but go for days and days without talking...
If you want to be with him, busy yourself and wait for him to come to you
when he does it'll be worth it