What Causes Fatigue Along With Poor Concentration?

Hi, I don't know if this is normal but recently I have been very tired and it's hard for me to focus on homework at home. I sometimes will get off topic and 45 minutes later realize that I've just lost a lot of time. When I think about the work I feel like my head is really heavy and just upset at the amount of work. I'm probably just burning out and stressed but I don't know what to do..