I feel you. I'm also constantly rerunning past conversations in my mind trying to find out what could i have said differently. It also comes with intense shame because i feel stupid about things i said. I allways feel like I talk stupid or nonsensical. I know it's not healthy because i don't make any productive changes about it, i just dwell on past conversations, and feeling shame "what people think about me". Though, like you, i still can't stop doing this.