as I said, eat some choclate and replenish you serotonin, just don't binge, that will make you even more depressed. *has choco cake, and gives it to Sekoshi*
EDIT: Another thing is play happy music and dance to it, even if you aren't the dancing type, everyone can understand it if you are busy doing dances with some happy music when you tell them the problem. For added effect, turn out the lights and grab some glowstix. The activity and choclate will definitely help, trust me, I've taken psychology.