It happened as i was driving home, i hot a pothole in the road and my check engine came on, then i came to a red light and the car RPM went down to like 0 and the car vibrated for a few seconds then went back to about 500. What happened?

 

You hit a pothole! Something probably knocked loose, or you managed to put your car in "safe mode" by hitting a pothole. Must have been a big hole you ran over to do that!