I am only in my young 20s and overall healthy. For the past 2 months, I have had excessive fatigue around 3 PM. I have tried everything: changing my diet, exercising more often, eating more protein, etc. I have a thin, athletic build and am not overweight. I get about 8 or 9 hours of sleep a night, so I am not sleep deprived. I wake up a ball of energy, but cannot function when 3 PM hits. I often take an hour nap, and force myself to wake up. My blood work came back normal.