I always wondered about the contamination of public water fountains. But I mean, realistically, I don't see how it could be tampered with to deliver any amount of anything besides water without there either being something obviously attached to it, or if the entire water supply was tainted somehow.
My guess as to what happened to you is that something went awry in your body's chemistry and caused you to have a speed-like freakout reaction of some kind. I'm no physiologist, but the human body is a mysterious and wacky thing.