When our son hit a wall his senior year in high school, he didn't know what to do. He had the lead in the senior musical production, other choir duties, concert tour, honors classes. One teacher had already told him not to expect to make an A that semester because of the musical, but not to worry about it. I helped him make a schedule of when things were due, which things were top priority and which ones could slide a bit. He decided which teacher to talk to in order to get some leeway in turning in work, even at a loss of points. He got through it, and the scheduling became a regular part of his life to help him get things done on time.

Just do the assignments and then they are done, and you can then relax. If you get into that routine you’ll probably feel better and more confident. Leave them and you’re anxiety will put you off

Get your blood checked. I had the same issues a few years ago. Found out I had medical conditions causing the extreme lethargy (tiredness)