Not at all. I had/have the same problem. The way I'm working through it is to keep reading shorter books on the same topics (i.e. intro books).
If I miss something important, it won't really matter because I'll pick it up from another book.
If I wanted to, I could go back an re-photoread the first book.
[I'm guessing that] Part of the problem is that you're still looking to read with 100% comprehension. It won't happen (not this soon anyway), so relax...
...which is what I'm trying to do.
