My shop hasn't been open that long, but when we were first working on fixing up the building and I had to make a lot of terrifying decisions, and was spending A LOT of money on stuff and I wasn't sure if what I was doing was a good idea... and so on and so on... I was about ready to check into a mental institution. I really wanted to just leave and go to the beach for a week or a month or forever, and I couldn't do it (couldn't afford the time, or money)... I was having trouble sleeping, and was a general crank to be around.... I realized that I needed some blank brain time every day. Whether it was watching an episode of Beverly Hills 90210 for the eighth time, or reading something totally unrelated to business, or rolling on the floor with the dogs. I try to avoid anything business related for at least one hour before I go to bed. It's hard sometimes, because I think that in order to have a successful business, you need to immerse yourself in it 24/7, but my mind just can't take it. Just the other night, I sat in bed for over an hour thinking about heating my shop this winter... nothing constructive was coming of it, and I just couldn't get it out of my head, I had to get up (at 1am!)and watch a rerun of Frasier, and then read some Stephen King for a bit, and then I fell right to sleep.
Sorry, I just realized how long this post is... I feel better, though. Hope it helps.