i get racing thoughts too, while manic and whilst depressed! it is extremely tiring, and the thoughts change from one minute to the next. One minute il decide i need to move town and the thoughts of where and how come racing in, then il completely change my mind and decide to study for a masters degree, then the thoughts of where il study etc, then il change my mind again and think i need to get a job…. all within the space of half an hour, sometimes the only way i can get away from it is by going to sleep. This is not a realistic solution for people who are at work/with kids etc but this is the only thing that helps me.