[Jach]

It's good to take into account the other comments, especially about changing your behavior. A lot can be done through sheer will and persistence (and training yourself to avoid distractions; yes you can do it and it will be painful so brace yourself), but not everything. I'll add a possibility that hasn't been said so explicitly: you aren't, and never have been, as smart as you think you are or were. Smarter than average? Probably. Von Neumann level smart? No way. You're a genius at best, not a supergenius. There are areas of human thought walled off from you forever unless advances in augmenting the brain arrive, it's that depressingly simple.