What should I do? Help please!?

I was eating so good today. I had a cup of Special K Red Berries with 1/2 cup of fat free milk for breakfast. I had a ham sandwich and carrots for lunch. For dinner I had about 3 pieces of meatloaf and about a cup of cauliflower. But then, my little sister wanted me to make brownies. So I did, and I ate more than half the pan! When I weighed myself, I weighed 5 more pounds then I did this morning. What should I do? I'm ready to starve myself so I can lose 10 pounds.