Did I [Almost] Pass Out?

This is a question I've been aching to know for the longest time. I didn't succeed in finding any answers on google and many forums like this one. Also, I'd like to add I didn't do any drugs around this time. So, here we go.

3 years ago - when I was in senior high school, the school had us go outside to do a rehearsal on some song. Well, I happened to be living in Florida at the time, and it was near 95°F that day. We sung and stood up for 30 minutes straight, no breaks.

After a while, I felt a sense of reality creating a glass room around me. What I mean here is that I felt totally out of place and a little euphorically annoyed, and that I needed to rest. The atmosphere of the feeling was alien and I didn't like it much, but I could still handle it.

Five minutes down the road, all I see in purple and yellow visuals. Everything that was dark was purple, and things that was lighter was yellow. At that point, I could of passed out at anytime. I even backed into the girl right next to me by accident, since I was in such as trippy state. When I was singing, I got lost in the words, and sang like a heavily tired mouse with a light but deep voice.

Now, you could ask "why didn't you stop". Well, I did, but that was after someone asked me if I was alright and walked me the to restroom to clean myself up. I was too stuck in the trippy state to function properly, or stop the task that I was doing (singing).

So, I'd like to recoup the causes that seemed apparent to me; key points:
• I was standing up the whole time
• It was 95°F
• I was singing
• I couldn't function properly, and I was too focused on my task to stop my episode
• Everything I saw was purple and yellow

If someone could describe how this triggered, and inform me on the name of it, I'd be VERY thankful. Based on my research, it must be rare.

Sincerely,
OC4000