On deadlines Whether the deadlines are real or artificial, they're usually a really good thing. Setting yourself deadlines keeps you accountable for the work that you're going to do. It also makes it work, though not in the bad sense of the word. Your writing is your work, and you should take pride in that. Your goal here is to be turning pro (see Steven Pressfield), not to do this as a hobby that comes and goes. You should set yourself deadlines as if there is a superior that you have to please, because there is. Right now, you seem to be struggling in understanding who or what that superior is, but either way, it is there. You know that this is part of what you're supposed to be doing. Perhaps you don't end up writing at all later on in life. That is irrelevant—this is your journey to get wherever you are supposed to be. Embrace it. Wake up and work hard. Enjoy it. This is your life. This is your reality.
On repeating study It's about time that you dive back into some of the books you've already read. The ones that truly changed you deserve to be repeated. You will find new things and solidify the learning you did the first time around. For example, Mere Christianity has easily been one of the most formative books in your entire life. It's a very short read, and I strongly advise you to read it again. Especially since you seem to be far from what you learned in that book at this point in your life. There's a paranoia that you seem to have with repeating study. You think that you should just focus on filling your mind up with as much new information as possible. You seem to say, "I don't have nearly enough time to go back and read this again. 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 not to return to these pieces. Especially considering the fact that you do have enough time if you would stay completely focused. Never use time as an excuse, because you know that 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 willing to repeat your previous studies. You will gain from it.