I'm right there with you. It's always so anxiety-inducing *before* the presentation, and instead of being relief that it's over, it was just a dread of "well now they think I'm dumb" *after*. The thing I try to keep in mind is that it's always a million times worse in your own head than the audience experiences. To you, this was maybe what you thought about for weeks straight and was such a big part of your day/class/job. You are your own main character. But to everyone else, you're just one of however many others. In a week, a month, a year, nobody's going to remember anything about it. You're not the main character to them, and this presentation isn't important to them in the long run. Even today, the worst someone thinks is "huh, that was different... moving on..."