Help! In deep trouble with rumors.?

Well it all started 3 days ago when I told a girl who I liked after she pestered me for quite a long time about it. I knew she was a huge gossip so I told her a fake name of a girl that was dating one of my "friends sort of". She spread it and it eventually came around the school and now im in deep trouble, how can I prevent anything from happening at this point even though i don't like her