find out who has been starting the rumors.. then.. find a time and a place where you know this person is going to be alone.. and confront them. Ask her "have you been saying ___ and ___ about me?" then she'll more than likely deny it and say "no, it wasnt me" then you'll say "well someone is saying ___ and ___ about me and it sucks, because it's not true. it just hurts that's all.. But i'm glad you're not saying anything" that'll throw her off so hard! she'll stop.. trust me.
Then go to the next person who you think is talking crap.. and do the same thing..
(yipes! did i make sense?)
Then go to the next person who you think is talking crap.. and do the same thing..
(yipes! did i make sense?)