Every writer comes upon times when every word is a struggle. I've had more than a few of those. I'm in the middle of the worst one I've had in a while. In this case, the words themselves come pretty easily. It's putting meaning to them that I'm having difficulty with.
I write a paragraph, and find myself straying from what I meant. I rewrite it, and question the purpose for writing it in the first place; the plan seems wrong. Then the next paragraph works well, but it's attached to the problem one, so is it supporting the whole, or is it a good piece attached to a bad foundation?
I'm probably overthinking things. Trying to get used to a new way of writing can do that to you, I find.