Pressured?

My friend and i have known each other for about three years, we're good friends but I feel that he and i were pressured. There is a holiday dance and I thought that there was hope for us to go out. I thought it wouldn't happen but i think my friends made it happen. They bothered him about it and he asked me on Friday. I said yes, but everyone seemed so much happier than me that we are going together.. (I'm regretting i ever said anything out the two of us going together.)
Now, I think our friendship is strained, and I don't know what to say to him. I feel terrible..I'd never want to hurt him, but it seems to be happening anyway. Things aren't the same.
I don't know what to tell him, I'm so confused about this.