Obviously, I've taken off more than just "a day or several." The short version is that I just have no will to write. I know it sounds like a lame excuse, but it's up there in importance. Quite simply, I just don't care. This isn't like a day job where I have a vested interest in going in despite my apathy; this is something that I do as much for my own sense of enjoyment and accomplishment as it is for the goal of someday getting published. When I derive no pleasure from it, when it feels like I'm just dithering and accomplishing nothing... There's no point. I can't make myself write if there's nothing there.
And right now, there's nothing there.