Over and over again...yes, you need to do that, no matter how much your brain is shutting down at times.
You have to do this hard part. You need to go over the same pages - again and again and again. You have to.
You sense what is either wrong, or at least not quite right, what gets off balance, what, when read by someone else, doesn't quite convey the intended meaning. Or the phrasing was awkward, or you lost a sense of perspective and put something there important to you perhaps, but not at all to a reader. Or you lost the thread, or thread(s) of the narrative because you got distracted, or absorbed somewhere that sent you off center.