I was just like you at 72 and through massive research and trial and error i distilled my recovery down to the carnivore diet and got almost immediately back on my feet. I now have renown allergy immunologist going through massive blood and urine search for culprits . So far they have 7 flags so that’s good as maybe they will be able to address them. Sounds like you have mast cell activation which has become common in post cOvid cases and post shots cases like mine. You might want to check out MCAS