I wasn't sure whether I'd be able to meet it, but earlier this evening I set a goal for myself: to reach 46,000 words tonight. And I did!
That means that I have just under 4,000 words to write tomorrow in order to reach 50,000. Since I don't have anything else that I simply must do before evening, I should be able to resume work on my novel right away when I wake up, hopefully allowing me to finish before I have to leave to babysit.
I had feared for a little while there that I wouldn't be able to finish NaNoWriMo this year - but it appears I might be able to, after all! Hoorah!!!