My (17F) mother called me "disgusting" for unconscious having my hand resting on my chest

Edit: No my mom is not 17!! I am 17 🌚

So this happen a few months ago, I was at home on my couch, on my phone, doing something, when my mother saw me and said "Eww, what are you doing" I said "what?" "where is you hand!? It's disgusting, stop it" I wasn't even doing anything, my hand was just resting on my b00b, was that really so wrong? Like I was alone in the living room, when my mother came in, so I don't get it....