Yep, it stays with you. What happened with my situation was, a dinner lady stood me up in front of the whole school, I was crying alot, and she said look everyone, look what a baby he is, and I remember everyone laughing loads out loud at me. And I had to stand there for about half hour like it against a wall. Just because some group in the year above were messing about. I wasn't involved or even saying anything. Now everything I do I doubt myself, it isn't just public speaking, it affects my work and like you, when I'm afraid to say anything incase I look stupid. It affects what I think people think of me. And I can tell its that because that same feeling comes flooding right back to me from that moment, it's weird...
I feel so sorry for kids who have had worse things done to them by weirdos or beaten and abused. I can see how it scars people for life. So sad. That dinner lady died of cancer anyway now, and I'm glad, some people deserve to die early