That overwhelming feeling you refer to while exercising happens to many people, I've experienced it too.
And if you are a person who experiences anxiety then that overwhelming feeling will continue to surface regardless of what you eat or drink.
The real advantages of eating and drinking good food is that you will feel better.
That overwhelming feeling is what preceeds the panic attack or should I say it is the trigger that is causing it to surface.
The solution lies in understanding and knowledge.
You said you talked yourself down, but it was more that you were talking yourself down while the overwhelming feeling was on its own way down.
Let me explain,
What goes up MUST COME DOWN.
Look up oxygen debt.
Now with this knowledge.
I like to imagine that the overwhelming feeling must continue to rise until it has hit an inner ceiling then once it has reached it .
Then it has no other option but to come down.
This works for me every time.
It's tough to know whether it was the caffeine, the workout, or both to some degree. I would stick to decaf for one thing. That way you get the benefit of coffee's antioxidants (and the flavor, of course) without the jitteriness and possible escalation into panic. But to answer your question, yes I once had a panic attack while exercising. It happened when I was really pushing myself running, lost my breath, and felt like I couldn't catch it again. Just like you, I talked myself down, but it was a setback overall. I would suggest getting back on the horse, but take it a little easy the next couple of workouts and gradually work back up to where you were before. I hope that helps. Good luck!
I also have high blood pressure