I'm 21 Year Old Male, I Lost All My Energy

I'm 21 year old male, I lost all my energy about a month ago. I can find myself getting out of bed for 15 hours a day while I'm not working. I have stuff I need to do but I can't bring myself to get out of bed or if I do still don't have the energy to complete any task. I'm not out of shape I'm 6,1" 236 pounds go to the gym almost everyday untel this happened. What could have made me feel so lazy