It sounds like you have an eating disorder, or may be developing one. The reason why you probably feel elated at the prospect of making toast, is that you know it will satisfy your father because he won't worry--since he presumes you'll eat the toast like a "normal person".
I don't mean to make a lot of assumptions, so correct me if I'm wrong, but I don't think your feelings aren't really that strange, considering your probable feelings toward food in general.