Good advice from Tess Gerritsen:
Tess Gerritsen’s Blog » Any way that works for you:

I’ve learned that the most important thing is to keep the story moving forward. Even if I realize that the story’s taken a sudden turn and I’ll have to go back and re-write three chapters to make the plot work, I just keep moving ahead. Only when I’ve written THE END do I allow myself to go back and fix things. The consequence is that anyone who sees my first draft may think they’re reading a half dozen different books spliced together. Characters’ names will suddenly change midway through (because I decide that I really didn’t like that name Olaf anyway.) Once, after writing about a third of a manuscript, I changed a character’s sex from male to female. Did I bother to go back and revise the early chapters? No. I just kept writing, using the character’s new gender.

Which is why a tool like Writer.app is invaluable. Get that? Invaluable. Meaning “beyond value.” Valu-ciferous. Which comes from the Latin: “value-giving, year ’round.” So you should pony up the $75… wait… it’s free. Pony up nothing, chum, and get writing. It’s not just me telling you, it’s Tess, too.

Go download it, get unplugged for a little bit, and see how far that novel gets then.