Well I hear you on this. It is sort of related to a thread I just started on horrible thoughts. I share your concern about driving. Only, it just isn't my own driving I am concerned about but it is that of others.
I am told I am a very good driver. While in the military I took a number of courses like defensive driving, safe backing, winter and bad weather driving, and so on. Years later I had a commercial driver's license. But STILL everytime I put my keys in the ignition I worry I might do something wrong.
*****I however have come up with a way to get around this.... I pretend I am taking a driver's exam and road test each time I get behind the wheel. While some might think, 'whoa! wouldn't this cause more anxiety?' I actually find it rather soothing as I think out ever move beforehand. It really does help.
There is one situation though that is still a trigger for me when I drive and that is when my boyfriend is a passenger. He conducts road tests (big rigs) and training for a living. He has never criticised my driving though. Still, I get really anxious with my stomach in knots. As a result I tend to suggest he do the driving
I suggest if you feel up to it maybe trying this pretend-you-are-on-a-road-test approach as I really do find it helpful. I pretend I am talking to the tester about my intentions and what I will do before I conduct them. This also helps me not get so irritated by other drivers as it is only my own driving I am concerned about.
I am currently driving in a city that is new to me and so don't quite know my way around. This has been cause for anxiety too but I map my routes out before hand. Not just the street names, but the major sights to look for.
Great luck. You've got this. Here's a pat on the back.