A few thoughts
Angel, a few thoughts:
Heart racing in some people (talked about in discussion forums) may be worse during times of flare-ups OR die-off of candida or some other parasite. It happens to me if I take a stronger antifungal at too high of a dose, for example.
Cutting carbs too low can overly raise cortisol in some people, (the paleo diet folks talk about this). By "carbs" I mean starches here. High cortisol can cause racing heart (and sleep problems).
Some supplements throw off the histamine balance in some people. There's a topic called Methylation that I don't fully understand, but for example niacinamide, one of the B vitamins, raised my histamine to the point of having 20 sneezes every morning. I stop the niacinamide and no more morning sneezes. Tried that a few times and it consistently caused the problem. There are a bunch of other supplements, that I don't use, that books talk about affecting methylation/histamine...is there any supplement that you started around the time your allergies became worse??
Acid reflux: some people get it if their gut bacteria/yeast is off, and certain types of carbs aggravate it in some people. Sugar/fructose over a certain amount gives me acid reflux, but starches never do, yet in some people certain kinds of starches give them the problem. Maybe worth experimenting? A book on Amazon called "Fast Tract Digestion" talks more about this idea.
Hang in there,
-North