what should I do?

so about a year ago I had a boyfriend. *note I am 15* I'm a virgin and plan to be for a while longer. I had this boyfriend and I thought he loved me, anyways I sent him pictures of my body. and he told people. we broke up after that, and then rumors were going around. i used to be "one or the cool kids" but now it's not really a concern of mine. whenever the "popular kids" come up to me and talk to me, it's usually asking if it's true or not. or about the added rumors. I don't want to lie, but I don't want to admit bc I know it was wrong and I'm ashamed of it. basically people know it's true bc of the ex. and I get flustered and nervous and embarrassed when people talk about it. also I used to get invited to parties.. now I don't. is it because people don't want to be around me bc of that? not sure what to do. advice?