gossip

M.P
Okay, I'm really upset. My brother got into my app and read some of the things I wrote on here about having sex. Apparently, he's been spreading and continuing to spread the word around to people at my church that I sleep around with a lot of guys. My one friend found out and told me. I don't know why I'm upset but it kinda hurts me. I am upset people know about my intimacy PERSONALLY (not just randomly online) and that she didn't stick up for me. She told me although my actions are "wrong". She believes what he's telling people is true and that it's okay, but he doesn't have the right to be telling others. She told me people are telling my family, "don't be like her," and shutting shaming me. 
I responded that there are many people doing this, and personally I don't think it's wrong. I feel like the only I'm getting called out for it. And she responded, "just because everyone is doing it doesn't mean you should". Anyways, I tell her everything and I think she tells people too. It's hard because she's a friend I keep telling shit to even though I know she can't be trusted. It hurts because I always keep her secrets and everyone's. Anyways, I learned to just keep my fucking mouth shut. I know I shouldn't let this get to me, but it's kind of hard to just ignore it. How do I handle this situation maturely?