You think everyone noticed. Most of them were checking their own reflection in the window.

You are the main character of exactly one life and a background figure in every other one. The trip, the wrong answer, the thing you said: you have replayed it forty times while nearly everyone else is busy with their own version of the same worry. Their attention was never pointed at you for as long as you assume.

Test it by asking a friend what embarrassing thing you did last month. They almost certainly will not remember, which is your evidence. Keep that in mind the next time the fear of being noticed is about to stop you doing something.