When you give up what has been your life to become a writer you hope for the best and know you'll just have to deal with all the baggage that comes with your decision.
What you can't prepare for, because nobody's warned you about it or written about it, is the guilt.
Just after Christmas I had a couple of weeks off to concentrate on research and some new ideas I'd come up with. It was a perfectly professional thing to do and what I achieved in that couple of weeks will hopefully one day help to deal with the aforesaid baggage. So why did I wake up every morning feeling guilty that I wasn't working? All day long my fingers would be itching to get back to the keyboard and start pounding away. My brain would be telling itself it couldn't afford to be taking this holiday.
It might be a hangover from the days in a structured working environment when, to a certain extent, if you weren't working you weren't earning. But the real answer, I think, is something I suspect just about every writer, no matter how successful, faces: the fear that if you stay away from a book for too long you might lose whatever it is that made you a writer in the first place.
When I finally got down to the serious job of writing my next book I felt a huge sense of relief when, after the usual jumpy start, the paragraphs started flowing and the characters formed in my head and began talking to me the way they sometimes do. It doesn't matter that I'll be more or less chained to the keyboard for the next X months, or that when I finally get up off the writing chair at night after X hours and X thousand words I'll be completely knackered. Because at this moment I'm still a writer.