In my 20's I had some problems with allergies, I began being allergic to silver out of nowhere, and then I had 3 anafillactic shocks of unknown cause. I went around with a ready syringe of adrenaline for years. I was very stressed back then, I also developed a severe gastrithis, when I resolved some pressing psychological issues and began to relax I also dumped the adrenaline. I'm saying this because I took many tests back then, and they didn't find anything regarding wheat. That's why I was thinking more of celiac disease than allergy or intollerance, although my symptoms might be a bit too mild for it.
The fact that you have had previous anaphylactic reactions in the past actually increases chances that the problem is allergic in nature. Especially since you were also taxing your adrenals.