Why??

My friend told me that I am acting like a slut again today because I have a crush on this guy but my ex broke up with me in January and I really like this guy but I don’t know what to do?? She said if I start dating him she’s going to tell everyone that I’m a big slut and say that I’ve been sleeping around, but I’m still a virgin! He asked me if it was true and I told him no but he said he doesn’t know what to think. Please help