PhidlDD,
Perhaps you could try relaxation and breathing techniques. Before you get into the car try a warm bath, or listening to soft music. Whatever relaxes you, is worth a try. Also you can pull a dry run. This indicates that when you get into the car, you will not go anywhere yet. Turn on the car, then turn it off. Next step is reversing out of the driveway and then back again. With each step you will make yourself go a little further.
Do these exercises at your own pace and what make you comfortable.
Hope this helps,
Josie