I'm with you brother, I've have something super similar. When I eat a full keto diet my symptoms subside. When eat carbs of pretty much any kind my symptoms flare up big time. Elevated heart rate, stomach discomfort, intermittent diarrhea/ constipation, brain fog, extreme irritability, what appears to be dandruff but is just the fungus on my scalp and beard, discoloration on toe nails, frequently injury when when training for no apparent reason. The list goes on. The gastroenterologist I seen told me that sibo isn't proven to make people sick, so complete waste of time there. Basically been fighting this battle completely alone. Recently it came back worse then ever. I feel like a hostage in my own body. I'm only 37 years old. With no end in sight. Beyond frustrated and been driven to tears multiple times. I'm sure I have candida as well as probably 1 or 2 other things.