Constant shaking and cold. The blood leaves your extremeties and goes to your torso and brain to conserve supplies. Your body knows something is threatening and needs to shut you down before you bleed to death. That's how shock works. Pain seems to be distant as well. In nature you'd crawl under a log or hide in a gulley somewhere in a natural response. Oddly enough you get sort of giggly too.
Oh yea, your so right. I was shaking, and obviously hurt, but still very calm and laughing, kidding around with the paramedics and the cops. It was so weird.