It’s about time you dive back into some of the books you’ve already read. The books that changed you deserve to be experienced again. You will find new things and solidify the learning you did the first time around. For example, Mere Christianity by C.S. Lewis has been one of the most formative books in your entire life. It’s a brief read, and I strongly advise you to reread it. Especially since you seem to be far from what you learned in that book at this point in your life.
There’s a paranoia you seem to have about repeating study. You think you should focus on filling your mind up with as much new information as possible, as if to say, “I don’t have nearly enough time to go back and reread this. I have too many new books that I need to read!” That may be true, and you should spend lots of your time filling yourself with new information, but that’s no excuse to stay away from these pieces. You do have enough time…if only you would stay focused on what you’re doing at any given moment. Never use time as an excuse, because you know you could be using it better. This isn’t a matter of whether or not you have time. It’s a matter of whether or not you are willing. We both know that. Be prepared to repeat your previous studies. You will gain from it.