I've definitely been there, the worst was one year as a teen it was 104, had a witch of a judge that was in shorts & tank top but required us to still wear hunt coats. I passed out and fell off my horse waiting at the gate for my turn in my hunter over class. She still wouldn't let us ditch our coats. I think that judge had something like 14 grievances filed against her for it.
I keep some of the gel packs that don't freeze solid on hand for really hot days. Wrap in a towel and put on your neck. Take a fan if you have electric hook up. Find a shady spot, ditch the jacket, cold pack on neck, fan on, lots of water & gatorade. Even when it's hot as hades don't skip eating (that's when I seem to wither the most) keep something cold and eat small amounts over the course of the day. Frozen grapes are a go to for me on show days.
Life is like a camera. Focus on what's important, Capture the good times, Develop from the negatives and if things don't work out, Take another shot.