Sleep is like a reset button. Whatever plagued you yesterday seems insignificant today. No, not today. That very moment when you wake up. Before you remember your worries, before the day hits you on the head, WRITE. Even if it's only for 1 hour. I know a writer who woke up at 5am every morning, before the baby roused the family, before he had to go to work, and wrote for 1 hour, finishing his novel in under a year.
I cannot talk enough about the difference it made in my productivity, this change of routine. I wake up. I get my coffee . I write. Okay, okay, before you hit me on the head for writing this in the morning prior to my writing, my excuse is, I was waiting for coffee to brew. So there. I got my coffee now. Into the abyss I go. Onward.