How many calories did I eat today? How many should I eat to loose weight?

Try to lay more off of the foods rich in fat. There are 2 types of fat: 1 bad, and 1 good. Its based off of the oils in the foods. The sunflower oil and other oils like that are a NO-NO. You could replace the muffin with a bowl of cereal (not the first ingredient being sugar). Try to have less sugar foods. Your dinner is fantastic by the way! Also you may just be growing... Good luck!