aw sweetie--I understand the need to push push push toward perfection. But it's all for naught if your brain won't let you retain it when you are this washed out.
I don't know enough about the particulars of your life, but I hope you find a solution soon.
I happen to be extremely noise and light sensitive right now, but I'm saving my pennies for this:
They ARE very pricey, but I've tried them and the effect is downright miraculous.
I understand "tired". So hugs.