Feeling full even when you haven't eaten much can depend on several things and the most common reason for this is digestion time and the food eaten the day before. If you had a heavy meal, especially one with cheeses and other hard to digest foods, you will still feel full the next day. The flatulence is also a cheese result.
Sometimes if you have alot of things on your mind or if your concerned about a certain topic.... Which would cause you to stress can make it difficult to eat as well.. I'm not suggesting that's your situation.. Just throwing that out there... :) XoxoX