Many years ago, in my early 20s, I was driving home from a weekend with some friends and my hands started drawing up and shaking, my heart started beating hard and fast, my breath was short and shallow and felt like I couldn't catch it, and my feet began to draw up, too. I was convinced I was dying right then and there. I pulled over at the first place I found, rolled my window down, leaned in on my horn with my elbow and did the best I could to flag down help.
A man ran over to see if I was okay and I told them no not even a little bit, but didn't know what was wrong. It so happened I had pulled into the parking lot of a veterinarian's office (how lucky) and a few of their staff came out and tended to me until the ambulance arrived. They ran a lot of tests in the ER and ended up telling me they felt it was a panic attack brought about by possible heat exhaustion, over activity, and/or dehydration as we had been camping/swimming/drinking. I never had another one that extreme even though I was in a similar scenario doing all of the same things many times.
That info isn't necessarily helpful, but I can relate to the weirdness of it being totally different than any other panic attack experienced before or after it. It's one of many things that still makes me go hmmmmmm..........
