Even though one night stands can be fun its only fun if that is what you both want.
In your case that clearly is not what you wanted but i would say it looks like what he wanted.
The fact that the whole of your school know and he is not now interested in talking to you first supports this.
Unless he was a very shy person i would almost expect him to say hi, how are you at the moment ect as ignoring a girl you just slept with is low.
Confront him infront of his mates is u like and make him feel stupid about it if he tries to put you down. If you think he used you then "remind" him of what a nervous reck he was in bed and it would of been more exciting to go and see Arnold schwarzenegger do a stand up night.
Don't let him put you down.