Absolutely!…..I have it….Mast Cell ActivationSyndrome. MCAS is everything you described and relentless without intervention. Great doctors in this area to follow, Dr Becky Campbell , Dr Beth O’Hara although there are so many more. They have the diets to follow and protocols for healing. I used supplements designed by them to reset my body’s chemistry. They, and many others btw, MANY…….will give you the diets to follow and when you veer off you get exactly what you live with daily. Mine was brought on by a lot of bug bites, when I moved , as well as really getting bad after each of the covid shots. I was not recuperating very well and getting depressed , and I went back to my roots of eating according to my blood type actually. I am O, which originated with meat eaters, so I did an extreme carnivore diet for a number of weeks because I felt so much better after just a few days. Shockingly better. Then began to get back to the protocol . I had the latest shot and sunk back to fluish and brain fog again, returned to carnivore for two weeks, recovered and now returning to more plant based . Doing well. I eliminated all dairy, gluten, and of course sugar and anything that turns to sugar. But it was the carnivore diet that saved me with each bout, without question. Eat Right 4 Your Type is a book I’ve been using for 20 yrs. I also have Ehlers Danlos Hypermobility and 40%of the folks who have this have MCAS. Best of Luck! This can end!!!