I just had my bipolar diagnosis changed to OCD and severe major depression, because I have repetitive thoughts and some are disturbing. My doctor put me on Luvox it is supposed to be one of the go to ssri's for OCD. To me it does sound like you may have OCD, I'm not a professional by any means, but I know in OCD it is very difficult to stop a thought pattern. From what I remember it is in the brain circuitry where signals keep repeating themselves, and normally after the person fulfills a task the brain receives the signal to stop via circuitry and certain brain chemicals being transmitted. In the case of OCD it is all different and message seems to go from the do to the done and back to the do and this can go on and on until...I don't know what stops this honestly. You can't really tell a person with OCD to stop doing this or that or stop obsessing it is the fault of the chemicals and transmitters in the brain.