You could start by reading your book when you find yourself thinking about therapy. Otherwise, concentrate on the now, as hard as that may be. I know how you feel. Its really hard to focus on anything except therapy when you first begin. Especially before you have a diagnosis or anything. But thinking about it all the time is not going to get you to the next appointment any faster.

Just do your best to focus on the things you can work on. Try eating right, setting a good sleeping habit. Go to bed at the same time and get up at the same time. Even if you can't sleep get ready for bed and lay in your room in the dark. And maybe take time a few days a week to go for a walk. All these things can help your moods even while you are between sessions.