I call it OCD, but I know it is just a symptom of my bipolar, not a separate diagnosis. I obsess compulsively over many, many thoughts. I call it the hamster wheel in my mind. CBT helps me with that, I am working on channeling my thoughts into constructive obsessions, and trying real hard not to disqualify the good. When I feel a deep sense of overwhelmed thought and rapid ramifications of ideas, I will make a list of any progress or anything good. Sometimes I just hold onto that and wait. I can't stop my mind, but I can guide it sometimes. Self defeating thoughts intrude my mind a lot, but I am working on replacing them with self esteem building thoughts. Lots of trial and error in that department, though I can tell it is getting easier.
This condition is called Overanalytical. That's anxiety and can be treated pretty easily. See a doctor.