Wow Wings I hope you're feeling better! Your story reminds me a great deal of my first time to the ER last year for shortness of breath and a very fast heart rate I couldn't calm down. It's interesting I had the EKG and it didn't show anything but I never had any of those other tests taken, wonder what would have shown up.
It's interesting that you're not supposed to drive until your doctor says so. I've found that any day I'm not feeling ok which is about half the time if I drive it sets off a panic attack very easily, just my own experience not sure if it would be a similar case for yourself.
Hope you get to the bottom of exactly what triggered it.