Since you've never reacted to wheat in the past, and know know that you still have trace amounts of wheat in your diet, I'd hazard a guess that wheat isn't to solely to blame. It could be the carb overload....all that fermentation happening, probably with a rich meal sitting on top of it...maybe some alcohol...the only way to know for sure is to clean up your diet for a couple of weeks and try it again. If you dare
I can say for myself that once I cut out grains, I can feel the effects of them now when I do indulge. Its nothing like you described, but I do feel the blood sugar rush, the bloating, the carb hangover, etc.