How can i loose fast pounds?

Ok, ok. My Graduation is comming up in 4 weeks, and i bought my dress a month ago, and it doest fit. Every morning i wake up at about 6:30 and i have a bowl of cereal or toast. I run for about 10 mins take a shower and so on, when i get home im crammed with homework, so i try to finish it in time so i can go outside and bike or something, but i only have about 20 mins before its too late. I need to loose about 50 pounds, with out taking pills or anything like that. how can i??