After some hours of being awake, i feel very weak and tired and feel like falling down. I don't feel sleepy but so weak that I just have to lie down. And if I sleep, I get back to normal. Also, if I eat or take some sugars, I feel much better but only sleeping then makes me feel energetic again. I have been having this issue for a long time, I take good food , sleep and exercise well. This is definitely not a lifestyle issue. Can someone please help me and let me know what the potential diagnosis could be. Thanks a lot in advance