I found out my whole friend group had a secret group chat about me for months

Me and this group of girls have been close since freshman year. Sleepovers, vacations, knowing each other's families close. I trusted every single one of them. Last week one of them pulled me aside and told me something that stopped me cold. She said there was a separate group chat without me in it. And in that group chat the girls had been picking apart everything I did for months. The way I dress. Things I said. My relationship. Who I was becoming. She said she'd been added recently and felt sick about it and couldn't stay quiet anymore. I went home and couldn't sleep. I kept thinking about every hangout, every inside joke, every time I thought we were all good. All of it had a completely different version running underneath that I knew nothing about. The worst part wasn't even what they said. It was that every single one of them looked me in the face and acted completely normal. For months. I hadn't said anything yet because I was scared of either crying and looking weak or saying something I'd regret and blowing everything up. But I also couldn't keep pretending I didn't know. I started thinking about what I actually wanted out of a confrontation. Not just to explode on them. Not just to make them feel bad. I wanted to know if any of these friendships were actually worth saving and the only way to find that out was to say something and watch how they responded. The response would tell me everything. Talking it through helped me figure out what I actually wanted from the confrontation. Not to blow everything up, not to make them feel bad. Just to know where I actually stood. We agreed the best next step was to go to them one at a time, starting with the ones I was closest to. Not as a group, not over text. In person, calmly. I wasn't going in looking for a fight. I was going in to say I knew about the chat and to give each of them the chance to show me who they actually were. Whatever they did with that would tell me everything I needed to know. I wasn't going in expecting a specific outcome. I just knew that pretending I didn't know was no longer something I could do.