I need advice... again

So this guy is walking around school telling everyone that he took my virginity in the locker room before gym. It’s my bully’s brother. (Does it count as a bully if every time they try to pick on you, you shut them down? No? Okay.) So I have never really talked to the guy and all of a sudden he “took my virginity”. I went to the principals office and they said they’d investigate but if it did happen, I would be expelled and I wouldn’t be in the Beta club or the student council anymore. I don’t know what to do.