I would really emphasize the effects of stress. If you even THINK you are losing it, your brain will hone in on every little thing that you could have done better, faster, more completely, etc. It will weigh heavily in the back of your mind and you will not even realize it. Then, when something like the work mistake occurs, it will all come flooding out and overwhelm you. You will convince yourself you are inept.

A dear friend (a professional counselor as well) gave me a book called "Why Zebras Don't Get Ulcers", written by a doctor/psych who would lie awake at night, usually around 3am, convinced he was developing a terminal brain tumor (as opposed to the friendly, non-terminal type of brain tumor!) At any rate, every night, he would imagine the tumour bigger, taking over his brain, wreaking havoc with his mind, so that every headache, eye itch, twitch, lost thought, etc., only confirmed all the more what he feared. He didn't have a brain tumor, but he did drive himself damn near crazy convincing himself otherwise. He wrote this book, which delves into our stress-filled lives and ulcer-ridden tummies. It was very, very enlightening. The body will actually manifest stress with physical symptoms even though there is nothing physically wrong. Incredible.

Lots of folks here have recommended Tai Chi, meditation, yoga, etc. These are good for anyone but especially those suffering from anxiety, worry, etc. Also exercise is very good, if you can manage it.

Put a plan together of the steps you are going to take to manage this concern and stick to it. Keep a journal and after a few months, review it. I would also journal in when you go to sleep and wake up, what you eat and when, and what kind of exercise you do and when you do it. This will help provide a clearer picture of how things are going. Good luck.