I have had the same problem in the past, and even now, I can't READ a book!
When I was taking classes, esp. those that required recovery of scientific content, I had to write things down, read it ALOUD, as in, SEE it, SAY it, repeat it.

I have never been diagnosed with ADD or ADHD, but I am sure I would fit the diagnosis. I'm 61, but even when I was in college back in the late '60's early '70's, I'd fall asleep trying to read texts, and long lectures were often tuned out from wandering thoughts, then fighting to stay awake.

I know there are medications to help with this. Are you taking anything?
I never have, and my attention condition has wavered often.