I had a dream of fighting an killing someone.?

At first it was about me going back too school an arguing with teachers. But then outa knowhere this man in my dreams in the hallway came out with a razor blade an tryed slashing me with it. He also didn't talk an he had his hood up. But I got the upper hand an got it awake from him an used it on him till he couldn't move but he got me a few times also. So after that I limp out of the school cause I was certian I killed the guy. An then I run too the other parking lot a few blocks from the school an saw my mom. But right when we started talking me an her a car came up in the lot right beside us real fast an then it stopped an then the dream was over. What does it all mean?