There's always a reason to procrastinate. As an unpaid writer with a nearly-fulltime job, I'm tired a lot. As a husband who loves his wife and loves spending time with her, I'm busy. A lot. The fact of the matter is, I have legitimate reasons not to sit down and write. Every day something else comes up that could allow me to say, "You know what? I think I'll just wait until tomorrow."
For that matter, I started this post early this morning. I'm so tired from a long day at work that I was tempted postpone this entry to Friday. And my EXTREMELY legitimate reason was that I need to work on my book. But I still think this blog is important, too. Especially when I get the opportunity to interact with all of you.
So when I'm tired every morning, and my wife wants to cuddle, it would be very easy to pull the covers over my head and stay put until it's time to go to work. I have deadlines, though. Sure, they're still deadlines that I set for myself, but they're important if I want to continue to move forward with my writing.
I guess what I'm trying to say is, every time you have time to write, take advantage of it. Doesn't matter how you FEEL, just do it. Eventually, you'll be able to work through just about any rough patch.