Anyone else really struggle to do their reading for longer than 2 hours

I’ve fallen behind on a lot of work and when I try to put in a concerted effort to read, I find that I struggle to focus and comprehend after more than 2-3 hours. It genuinely becomes impossible. I have to constantly re-read sentences and I just don’t understand what I’m reading.

It’s really hampering my ability to study because 99% of my course is reading and I have a lot to catch up on, and a lot of work ahead.

I do law btw