My GP gave me a couple of those quick 10 questions mental health tests when I saw him about major anxiety attacks. He said I scored a little high on the BP test and refered me to a psychiatrist. It took about ten minutes for my psych to rule out BP and suggested ADD (No H, as I'm not hyperactive)

The racing brain/thoughts and low self-esteem are certainly common among us ADDer's. I used to always think I was one mistake away from losing my job, like I over-sold my abilities and would eventually be discovered as a fraud. BP and ADD have a lot of shared symptoms.

As for a little help...
Exercise makes a HUGE difference in my ability to focus, even now that I am taking Adderall. The games here at PC also take my mind of my worries

I hope you find some answers