panic panic panic

Everyone loves to moan about their childhood. Bullying, isolation, academic underachievement, everyone seems to have a pet gripe. I'm slightly weird them when I say I actually quite enjoyed being a kid. Oh sure, there was the usual pigtail pulling and name calling in the playground (especially by one particularly nasty little blond) but aside from normal ups and downs, I was generally happy. Even in the unpredictable phase of adolescence I didn't get my heart broken more often than anyone else, I did well at school and had plenty of friends.
My self-confidence wasn't too battered: I agreed to sing, perform in plays and make speeches in front of people, sometimes hundreds. So what happened?? Why now, when I am supposed to be a fully fledged adult, am I terrified of performing to an audience? Why does the fact that I am presenting my past four months' experience in Poland at an international conference next week send cold chills all over my body? Why does the fact that the room can hold a couple of hundred people get my heart racing? Why do I find myself desparately searching for a plausible excuse for dropping out at the last minute?
When I break it down logically I get annoyed with myself. It's just people! They're no better than me, and may even learn something from my presentation. I'm obviously young, so they'll make allowances for cock-ups and anyway, there won't be any cock-ups because it's all planned out and perfectly prepared.
I think it's the lack of control, or the risk of losing control in front of an audience. That's why I don't get so nervous about plays - as long as the script has been learned, it will follow a predictable route. The problem with presentations in comparison is the audience participation. The way round this is to take control away from the audience I guess. Make myself believe I have all the control I need and that there is nobody who can think of a question I won't be able to answer... Focus on myself and not them. Damn though, just thinking about it though and I get the shivers.
I'll try the tricks. You know, the imagining everyone in the audience is naked, or wearing costumes that make them ridiculous. Bit negative though isn't it? Maybe I'll try the positive thinking approach; imagine myself presenting, the audience beaming, my powerpoint working perfectly, no nervous giveaways and my heart beating at a normal pace. Hm, think I'd better keep practising...