What do you do if you don't feel like going to work? Majority of the time, you go to work. And you start working. And it may not be the best workday ever, but you get something done.

Sit down, write words. They might suck. It might be a half-hearted attempt. They may have nothing to do with NanO. Write about why you don't want to write. It doesn't matter. Write them anyway.

Edit: Full disclosure. I'm miles behind in Nano, but that's a choice I make every day. It has nothing to do with feeling like it. But it a deliberate choice. It doesn't have to be YOUR choice.