I'm going through the same thing
I wasn't dumped, it was a mutual thing, but it's still bloody painful. Worse, I'm home for the summer and can't find any friends to go out with as they've moved on and away. I'd love to start work full time (I graduate in Sept) but I have a dissertation to sit down and write, which isn't the best distraction I can think of!
Try spending if you can - I extended my overdraft and did some shopping, which helped. I bought a mountain bike, which has been fun. Also bought stiletto heeled boots, which boosted my confidence, tho they hurt if I wear them for longer than a minute!
Also, my relationship lasted the whole of my four years at St Andrews, so coming home (although there's no one here) helped for a bit as it took me away from all the reminders. I've played 'I Will Survive' a few times - it has to be done.
Having suggested all that I'm still pretty down at times. I think you just have to try and be strong and ride through it. There's plenty more (better) fish in the sea.
Hope that helps!
Sarah