I kinda dealt with this a little when I was learning. I'd feel pressure in my chest and my adrenaline would be rushing. I was also driving a 3 ton 18 foot long van too. The first time I ever drove legally as a learner driver was in an empty parking lot at a factory near Six Flags of Midamerica. There were a few cars in the lot, but there were no people and only one vehicle ever moved while I was practicing. After that, I moved up to driving around a subdivision. From there, I moved onto a public street (I was scared out of my mind to go from 20mph up to 40) and quickly got to highway driving in no time.
Panic attacks while driving is not a good thing though. Even if you are able to conquer the fear of driving, I'm very certain that you will simply lock up in an emergency situation and have no idea what to do.
