Hi Edabitit. I was your age when my periods stopped. My doc ran homone tests and said I was pre-menopausal. I've never had a period since. Bout 2 years later my lupus symptoms started so I think mine was lupus related.
I've had some alergic reactions, but nothing like you describe and I really feel for you girl. It sounds awful. I'd ask your doc to run the female hormone tests; it can't hurt. As for the heat, I have that too 5 months of the year. The slightest bit of exertion makes me so hot my hair is soaking wet from the tops of my ears down. And there are others on the forum with this too. As for the prednisone it's a drug with some nasty side effects, but if you're in a flare, often times you just have to take it. Lastly, I hope you are seeing a rheumatologist. You may have fibromyalgia which can cause intense pain throughout your body. I have lupus and fibro.
I was healthy before lupus. I ran for 20 years then took up swimming. Prednisone increases my blood pressure and my blood glucose so I must take drugs for both. You just have to weigh the pros and cons of pred. Sometimes it's the only thing that will bring you out of a flare. We joke here that someone is always online because pred can keep you up all night. Well I think I'm rambling now- must be the pred Love, Butterflake