There is a moment within revisions when you are not really sure if you are going to ever find your way out of the cave... maybe a tunnel is a better analogy. So you start revisions and it's like "oh great! I am going to walk back into this tunnel that I think I know well (because it is a book I wrote) but with a map annotated by one or several other people! I think i will get to the other side of this tunnel quickly and easily."
Basically, it's super easy to walk in, get cocky, and end up completely turned around until you have no idea which way is up, much less which way is out. You hit that point where you know "the only way out is through" but you also aren't even sure what "though" looks like. Basically, it is The Worst and The Struggle Is Real. You are in the depths of writing despair.
I have been here before and I will surely end up here again on this or other stories. But I have also found my way out of the cave/tunnel before, so I know I will this time. But it is still a good thing to acknowledge and just keep powering through. I leave you with a great tweet by an author I really love...