So, for the newbe, and mainly a runner, what is a bonk? I went on (just a usual) run on monday... I can't believe how bad I felt. I mean, there's just no way that I "hit the wall" - I just didn't go far enough, but man, I barely made it home. Maybe it was heat exhaustion (got goose bumps and almost stopped sweating) - but I kind of think it was a food / water thing. Will someone define bonk for me so I have a nice shiny new label to put on my misery