11 pages down and 300+ to go

I have been diligently plugging away on my novel and managed to write 12 pages worth since last Saturday. This is pathetic. I tend to write a paragraph, stop, read it through, make some edits, re-write, and then move on only to return to the original paragraph and do more edits. No wonder it's taking me a long time to write 15 pages.
Yes, 15 pages that I need to submit by midnight tomorrow. I lack the discipline to just sit and write. Not edit. Not read over what I wrote. But to write and write and not stop until I have some semblance of a story.
At least my outline I drew up is helping me along and 12 pages really isn't that bad. Three more to go..