A dropping blood sugar could certainly cause those feelings. Dropping from 300 to 100 would feel (I'd imagine) the same as dropping from 230 to 30 in a short amount of time.
Or it could have nothing to do with D whatsoever. I remember once I was going to work on the subway in NYC and I had a similar experience. I don't know if my body was "violently" jerking, but I think I was moving a bit involuntarily and was clutching the pole to stay on my feet (as you have to do anyway on a crowded rush-hour subway). I remember trying to focus on the destination sign (the digital sign that tells you what train you're on, the next stop, etc) and it was fading to black and coming back - it was the only time I could ever remember my vision disappearing like that. At the next stop (whichever it was), I pushed myself off of the train and sat down on the platform for a few minutes. I was in a cold sweat, I checked my BG (I forget what it was, but it didn't seem alarming), drank a bottle of water, and when I felt able, I hopped on the next train to get to my destination. Yeah, I was scared, and quite shaken up even after the fact and I don't remember too much about it. Thinking back, I remember leaning against a booth on the platform and explaining to a guy why I was there, and later on I tried to figure out which stop that was. I clearly didn't know at the time.
I'm not quite sure what caused it, but I suspect that some new medication that I had been taking for IBS (irritable bowel syndrome) may have caused me to become dehydrated. I forget what it was called, but I never took it again and haven't had anything close to that happem since.