I usually have about ten books going at a time, all different genres so I've got something for any mood. I average a book a day over the course of a year. I often take a break from one book by reading another book. :p My students find this endlessly amusing.
How do I do it?
1. I'm interested in everything. I love learning in all areas, so I usually have a 70/30 ratio of nonfiction to fiction these days, but I used to only read fiction (I was a lit major way back when).
2. I am good to my eyes: I've clearly built up some reading stamina with my regular reading. I limit my backlit computer reading, and I read in adequately-lit areas.
3. I have ADHD. One often forgotten symptom of that is hyperfocus. When hyperfocus doesn't happen, I might read while on an exercise bike.
4. I learned that nonfiction is digestible in audiobook form. I can't stand fiction audiobooks. This allows me to "read" while exercising, driving, or grinding on a video game.
5. I don't do social media. I keep the sound off on my phone.
6. I sometimes read socially (book clubs, recommendations from friends). Knowing I'm going to talk about a book is motivating. I also am always motivated to expand my repertoire so I can match the perfect book to a reluctant student reader.
7. I abandon books that suck or make fun of them, depending on my mood.
As far as a diagnosis for your problem:
1. Three of your books are similar subject matter. That may be overkill.
2. Harry Potter is overrated. One and three are good. The others? Meh. I enjoyed it along with all the excitement, but I don't think it really has as much staying power as people think, and it is certainly lacking in literary merit in most of the books. If you find yourself easily putting it down, try something else. Do you specifically want to read fantasy? Young adult/children's lit? Adventure? Talk to your librarian for recommendations.
3. Consider the translation of the Bible you're reading. Some of them are really quite bad. The New Jerusalem translation is my favorite as it maintains the poetry of the original languages well. If you have to read a bunch of begats, at least they can be in pretty sentences.
4. Your eye stamina is probably compromised. People use different eye movements to read on a computer/screen, and it effects how they read print texts if they don't keep up with that kind of reading. You're going to have to retrain so that you're not missing the right side of some paragraphs. One way to do this is to slow down for a while. Also, reading, when you haven't built up stamina, can make you tired. That's normal. Start with, say, fifteen minutes at a time, distraction-free and fully concentrating on the content, rereading when you get distracted as needed. When that becomes easy, do twenty minutes, etc. Reading is incredibly hard work, and people take it for granted that our brains can do this amazing feat once we've learned it even if we don't keep in reading shape. That's simply not the case.
