How to handle disappointment: just started dating a guy, everything was going great however I have not heard?

from him for four days now. I texted him on Sunday, letting him know I am thinking about him but he did not reply. So - I have the inevitable heart ache to accept the situation and move on. Just want to know how does one handle this kind of disappointment? I mean, I have a life, loads of friends, activities, hobbies / cles and I work (so not bored during the day - but the heartache / disappointment is distracting), so besides keeping busy, what else can I do?