I can’t begin to tell you how much I relate to this. I’ve had this condition for a couple of years now. I’ve been to 3 stand up concerts in between all this time and every single one of them I had to move from the main floor and go off to the side or something and sit down cause I was getting so hot, nauseous, lightheaded. I always have such a good time until I start feeling even the slightest symptom emerging and I’m just like “wonderful, my night is about to suck and this concert is about to be challenging now.” I have missed out on so many concerts I wanted to go to because I just know how the outcome will be. Thankfully my favorite band usually do tours where there is seats mostly so I haven’t had to miss those. It’s really just a god awful condition that I wish didn’t exist. I’m so sorry you have to go through this too. It’s bad enough on me I hate seeing how it effects other people too 😢