I know the feeling! My to-do list is staring at me, and anything that requires sustained mental effort is left undone. Surprised? Me neither. I also have to do a TON of reading for school, and it takes an act of Congress to get me started. The good news is, if I DO get started, I'll usually keep going for a while. Just opening the book, or writing a title at the top of a page, helps overcome the inertia.

One thing I've started doing is the Pomodoro Method. Basically, you set a timer for 25 minutes, work as hard as you can until it goes off, then take a 5-minute break and come back. I use a phone app (Pomodoro Lite) to help me.

Good luck! I hope you find something that works.