It's ok bro. You were just nervous, and that guy was a dick. Try to relax before taking it again, and do it at a different place, you don't want to risk getting that guy again.
Sounds like the guy over reacted or you waited more than a second. Anyhow, I woulda refused to take him back........prob woulda taken him hostage until he signed you as passed. Remove bodyparts of necessary..........
What happened to you was pure bullshit if you are telling the truth. Anyone who has driven for more then a week knows that you should wait for a moment after the light turns green because some times people going the other way will gun it at the last moment.