*gets out the cookies and hot beverages of choice for everyone* I think we need a pep talk from the archives of NaNo.Neil Gaiman's Pep Talk
And if Neil Gaiman doesn't float your boat, here is the archive of past pep talks
For everyone that feels that they are too far behind, I believe you're going to make it. It might look like a long battle, but I've been where you are. In 2008, I lost a week of NaNo due to being sick and exhausted from a long volunteer opportunity. When I could sit up, I tried to just get out 50 words. If I could do that while feeling like crud, then it was a victory to me. As I got better, I was able to write more and more words. So, if you feel like you can't do anything, then try to write 50 words. Then, make room for more of the 50 word sessions and, when you're able, try to up it to 100 words.
Also, that works for anyone who is having problems trying to get the words out. It's one of my favorite exercises and it works like this: Open your novel / chapter file in your word processor and write 50 words If they go well, do another 50. If they don't, give it ten minutes to see if you can get a better replacement 50 or an additional 50 you feel is good enough to keep. And then you can shut the file and do whatever you want as long as it's pleasant. You did something on your novel, you deserve a reward. If you're enticed to go back to the novel, great. But try hard not to let the next 24 hours (or preferably today) end without 50 new words in your novel. It really doesn't matter if you dislike them and might delete them later, just make an honest effort.
Of course, if you feel you can't do 50 or think 50 is too low, substitute your goal of choice.