Can you get back in touch with the people who were providing the CBT and maybe get a refresher? Just from your description, you actually sound like a hard, intelligent worker -- you're obviously very conscientious about getting things right and how you spend your time.

I am now in my mid-30s, but when I was in my late 20s, I was in a similar position. Like you, I had always done well in school and work. I wanted to do something more fulfilling but was scared of leaving the money.

My situation was slightly different. I left a large company where I was a superstar for a position working for an abusive boss in a very small company. I was okay at the work but constantly scapegoated. I was responsible for quality control on a product which was produced by people who were incapable of quality production. As I was blamed for missing defects, I started to make more mistakes. I started to get lazy about doing my work. By the time I left that company, I was wholly unmotivated and felt stupid and generally bad about myself.

It sounds like you are in a much better position with superiors who like you and appreciate the work you do. I can't offer anything about how not to feel like a fraud, but you aren't alone in feeling that way. I see people who have less experience in certain areas than I do proclaiming themselves as experts, yet I can't do that myself.

I tried a few things to make up for feeling lousy about my job situation. I started a graduate program at the local university. If your company has any sort of tuition reimbursement, take them up on it, if you can.

I also started to explore some lifelong interests that I had always set aside in favor of more practical goals. You may not have the time, but you do have the money to explore those things you've always thought of doing 'someday.'

I eventually saved up enough money to take a year off (but still pay my mortgage). It was the best thing I ever did. It completely changed the way I view my life and the way I work. I went back to being a superstar at my next job... which I also quit, in favor of finally working for myself. I worry so much less now than I did before. The relief is overwhelming.

You might like Barbara Sher's books about 'seekers,' people who feel like they are interested in everything or whose interests change every six months.