Been there with a similar reason, my relationship was 3.5 years long. Somebody else on GV had asked the same question, and I'm gonna give you the same answer I gave them.
Start working out. I used to work out almost 2 hours every day when I had the breakup. I don't advice on going on for that long, but try to work out for 30-60 minutes 3-5 days a week. You get a better hold on your emotions, it helps improve sleep, provides immunity over your shit feelings for a good few hours every day. You eventually get into better shape as a added benefit.
Feel better, take care :)