Hi Beautiful Bird,
Welcome to the site. It sounds like you have some great coping mechanisms and tools already in place from your previous work on panic attacks, like how you keep an attack from coming on the grocery store. All of these tools will be really helpful as you learn to get better at freeway driving (which yes, you definitely can!).
You are right that panic attacks can be a strong signal that we need to slow down and figure out what is really going on in our minds and bodies. If they started for you during your divorce that makes sense, because intense periods of stress can bring them on. Sometimes, though, you just "learn" to be anxious in certain situations, like in your case driving on the freeway. It's hard to unlearn this fear reaction, but it CAN be done! Driving on the freeway long distances from home is one of the tough things for me to do, too, but I'm getting better at as I've worked through the program on this site.
I hope you will start the sessions here, and work your way up to session four which focuses on exposure work. The type of anxiety you describe is perfect for developing an exposure program to help you unlearn your fear of freeway driving. For example, you might start by driving with a safe person, then drive one exit by yourself, two exits, etc. over the course of several weeks or months. I won't go too far into it here but it's the part of the program that ended up helping me the most.
Keep us posted on how you're doing. This support group is an invaluable resource!
Teebs