Mate, don't sweat it - a lot of guys have been dumped by their (former) girlfriends.
My last girlfriend dumped me over the text, while I was spending some time with my best mate which was a huge help. At the time we were playing a couple of video games (preferrably FPSs) which really helped to take out the frustration. I also listened to more hard rock style music at a loudish level which just lets you take your frustration out.
The best thing is just to spend time with friends, go out and as thegreenmonk says just enjoy the single life.