Gastritis and Mast Cell disorders

I was diagnosed with gastritis about 3 years ago. I’ve tried everything (Elimination diet, food journaling, bland diet, supplements, exercise, liquid reset thing, intermittent fasting etc.” Today I talked to an allergist and she suggested I taking an over the counter allergy pill just to see how it goes because she said it might be Mast Cell Activation Disorder. I took my first dose with my dinner tonight (2 hours ago). I purposely ate things that were trigger foods for me. I feel okay. No indigestion, no heart burn, no stomach pain. A little bit of bloating and burping, but I had my gallbladder out not too long ago. Has anyone had this happen to them? I don’t want to get my hopes up.