My mother told her friends a humiliating secret about me. I'm so pissed off I don't know what to do. Any advice or anyone have a similar experience?

There's a TL;DR at the bottom, so you can skip to that if you would like to save time. I'm just angry and upset and need to vent, throwaway account by the way:

I had a deeply humiliating experience when I was 14. I was getting a physical exam for the first time since I could remember, I has going through puberty, and the doctor was an ok-ish looking woman. You probably know where this is going, so I'll just go ahead and tell you that I ejaculated during the course of the exam. And my mother was in the room too (I was nervous as hell so she asked me if I'd rather her be with me and I regrettably said yes).

The doctor didn't even flinch, she was a doctor after all, but I was horrified and humiliated. I was actually in tears from embarrassment on the way home and I didn't get over the incident until a week had passed. Fortunately my mother was understanding of how I felt and promised she would never tell a soul, so I was confident that the whole thing would stay between me, the doctor, and my mom.

That is until last night. I was trying to sleep, but could over hear my mother and four of her friends chatting in the kitchen (they never realize how loud they are). Just s…