The way to tell if you lose weight is to weigh yourself, keeping track over time.
Muscle weighs more than fat, so if you build muscle mass faster than you burn off fat, you'll actually be heavier. Losing weight shouldn't really be your goal, your goal should be to be healthy. If you can run for 2 hours every day, you're probably not fat. You may have a problem with your self image.
Ask the people around you that can see you (because I can't) if you're fat. If they all say no, your problem may your perception of yourself.