I'm at 22K for my NaNoWriMo book, and my character has just gone through his absolute nadir. It's been my worst--hardest, most hari-kiri inspiring--day of writing, too, although I got it all done for the day.
Traditionally, your character's worst ("black") moment is supposed to come right before the big fight scene, and the hero resolves all his inner problems right before beating the crap out of his external ones.
But no. This is more like the moment in Star Wars when Luke is in the cave in the swamp, facing down Vader. Things get worse from there, but he's never as lost as he is in the swamp.
I had planned for something different, something with more action to it, but once I was down in the trenches, I could see it wasn't going to work. You just can't force the character through a 180 for the sake of plot. So instead I went the more difficult way, and bleah.
It's days like this when I think, "Why would anyone want to read this?"
This book is terrible.
You're irresponsible. You're wasting your time. You should be spending more time with your family.
You're too old. If you were meant to be a writer, you would have succeeded by now.
And on and on...
So I just tell myself, "If you finish this page, you can give up."
"If you finish one more paragraph, you can give up."
I curse myself. I know I'm lying. This is the kind of day where you keep finding gray hairs.
But hey. As hard as it is to write this stuff, at least I'm not my main character. His life sucks.