Hi redsilk
CBT is about challenging your thoughts but its also about training your thoughts to be different about what you are feeling too.
You said:
[i]When I was well, the reason why I could do so much was simply because I didn't think in the first place! [/i]
This is partially true, you were thinking but most likely they were positive thoughts, directed towards things you were doing, going to do, or wanted to accomplish.
With anxiety and panic your thoughts are now focused within, introspective, worrying about symptoms and then fearing how you are feeling.
Being on high alert and listening in to the slightest strange thing,monitoring your body, waiting to see if "it" will begin, this is what you are doing now. CBT will help you learn not to continue this thinking, and how to replace it with thoughts that you are okay.
Dont expect things to change overnight, you built up to the anxiety/panic over a period of time, so unlearning those fears takes time too.