Dissertation frustration

I'm having a lot of trouble with the chapter of my dissertation I'm currently writing. I feel like I know what I want to say, but every time I write something down it doesn't fit with every thing else. It is so fragmented. And now I'm confused and frustrated. I really want to get this done by Monday...at least written by then. Then I can leave it for a few days. But as it is now I'm suffering through it every day and I can't get a hold on it!! I fear I may lose my cool with this one!