I know what you are describing. I'm not yet diagnosed with MS, so no idea if it's related - but this happens to me at every sign of upset. I get so bad that I shake visibly and my heart starts POUNDING like crazy. It takes several minutes to wind down afterwards, and almost always ends up with me having a headache and my gut feeling wobbly.
Example: I had a customer in my store last week. She came in guns blazing -- She bought something at another store (we're a chain of 15 stores total). She was unhappy with the product. Nothing to do with me, my store, or the way I manage my staff. Theoretically, it should have been easy to not get upset. She wasn't unhappy with ME or my store - just the product she bought elsewhere. Because of her attitude and how forceful she was, however, I immediately start shaking and I can hardly talk. My heart is pounding, I can't think, and it took AGES to calm down again. STRESS does not cover the feeling.
I'm normally not a 'stressful' person. I'm pretty cruisy and laid-back. But for some reason, I seem to get these HUGE rushes of adrenaline even when un-called for. It's like my fight or flight response goes into overdrive. Hmmm... you've given me something to think about. I never thought to ask a GP about this... I just figured I was being a bit of a wimp.