The blood test for celiac isn't very accurate, but the biopsy is, so it depends on which test you had. also you can have a wheat allergy and not have celiac. I feel better when I avoid wheat, although I am not celiac.
The arrhythmia could be just triggered by a gas bubble in your stomach. The gas bubble is what I noticed first, but I also had a bunch of food intolerances which started the heart going fast and the stomach refluxing. It took me months of recording my foods to figure out that half an hour to 2 hours after eating I would get reflux from a large list of foods. Certain meds, including OTCs will do it too!
I saw a cardiologist who had me on a monitor for a week, but it never recorded an arrhythmia since the radio signal was on a cell phone frequency that isn't available at my house - so the monitoring company got a signal every day when I went into town, and they said no arrhythmia. The 24 hour Holter monitors aren't much better because you might not have a problem on one single day. But they're worth a try!
I have no clue about
the hair loss, although I have it as a senior. Maybe an endocrinologist could check your hormones.
Before starting on acid reduction treatment you should see a gastroenterologist.
Bloating and gas can be caused by a huge list of "gassy foods." You can do a search for the lists. They have mostly complex carbohydrates. You might try avoiding them for a while, maybe reintroducing them one at a time. Understanding these foods is key to avoiding bloat. I didn't realize that the artificial sweeteners did this - because of the dextrose in them which we don't digest but the bacteria do! Soluble fibers are digested by the bacteria too! And of course sodas, which give you gas in the stomach.
Other causes of gas are gallbladder, appendix, and celiac. "Cures" are probiotics - like adding yogurt. But that doesn't stop everything.
Well, that's enough for you to research for now. Do see some doctors! I'm not one!!! We're just all patients here, and our stories are just personal experiences.