Everyday I wake up I feel like I just ran a marathon. My arms and legs feel weak, tired, and heavy. If I sit for a long period of time I get very stiff mainly in my legs and arms and it's hard to get up. I only feel better when I move around or do some exercise. I always feel like I need to take a nap. A couple of months ago I stopped exercising and I keep eating smaller and smaller portions of my food as a result I have lost some weight and now none of my jeans fit me any more. Please help. I hate feeling this way and I am not eating less on purpose. Im 16 years old