I was the same way for a long time. Most of my childhood and some early adulthood. I was afraid of people hearing me use the restroom and of people hearing me breathe to the point where I would pee in unorthodox places because I physically couldn't in public bathrooms and I would hold my breath when a room was quiet. I couldn't have sleep overs because what if the bathroom wasn't private enough? And I can't control my breathing once I'm asleep so, what if I'm first asleep? It's like I was afraid of showing that I was human. My extreme general anxiety aside, I think it had to do with high expectations put on me as a kid. I was like family decoration. Emotionally neglected asf and expected to be perfect all the time. Using the restroom made me feel vulnerable and exposed, and so I'd only ever use the bathroom in my childhood basement or bushes far far away from people. Several years after I moved away from home something just clicked for me and I could use public restrooms, and I also didn't have to hold my breath anymore. Hang in there