I've made out wit this boy, and now I've got a bad reputation. What should I do?

What should I do? One night, in the beginning of my freshman year, there was a football game. That night, I made out with a boy I hardly knew. My reputation is tarnished. I know I shouldn't have done it, but something made me lose control. I thought I was immune to pressure. I know I made a bad move, but I know I'm not a slut, even though I've had a couple of boyfriends. Really, I went out with them to be nice. I'm afraid that this reputation will damage me. I cried for so many days. What should I do and I cant transfer schools?