Scuba diving off a boat in Monterey bay California, I was heading for the bottom, head down when suddenly I felt like I couldn't get enough air.
At 50 feet I stopped and tried to get enough air and regain my composure, I sat there sucking in as hard as I could while trying to remain calm. I was in some sort of panic at 50 feet, every instinct in me wanted to shoot to the surface, finally I was able to calm down and slow my breathing.
Apparently this happens to many people and I am told made worse by heading down head first.
Not a good place for a panic attack