I don't know how it is with you, but when I'm quite busy at work I just don't feel the inspiration to write. Not a novel, not even a blog!
For me, writing has to come freely. And I can only reach that state when I don't have anything to do (well, not counting a trip into the town center to do my shopping, or the ordinary tasks in the housekeeping). But then my mind is at ease and I just need to sit behind the keyboard. The letters just flow on the screen.
Right now, I come home from school and don't feel my feet anymore. There is so much to do and it's there you feel you are getting older. Years ago, I still had the energy to do other things during this busy month at school. Now I love to sit down and read, or watch a bit of tv.
What about you?