Had to sit down at an event and it frightened me a bit

Went to a night at the weekend, first proper one, and about two hours in I went from having a great time to feeling very odd very quickly. Hot, slightly dizzy, and with the strong sense that I needed to be somewhere else immediately.

I got outside, sat on a step, and after ten minutes or so I was completely fine. Went back in, stayed another hour, and got home without any trouble.

But it has rattled me. I am not sure whether that was the latex, the room, the fact that I had barely eaten all day, or nerves. Is this a normal thing that happens to everyone once? And what do people actually do to stop it, because I would like to go again and not have that happen.