There's thinking about therapy/therapist, and then there's obsessing/fixating on therapy/therapist. Thinking is good and can be very constructive; fixating probably needs some sort of intervention. You have to find other outlets for your brain be that reading (something non-therapy related), puzzles, good movies, socializing, meditating, exercising, etc. Give yourself permission to spend a specific period of time each day thinking about therapy specifically, but try to keep that appointment with yourself and use your other time for other "appointments" with yourself. Takes a great deal of self-discipline, but it is doable.