What you describe: “Itching, wheezing and stomach pain”, is not anaphylaxis. That term refers to a much more violent, systemic body reaction.
Nevertheless, what you have experienced certainly sounds like an allergic reaction and it must be very distressing. I suggest that the problem may well not be food allergy and that you and your doctors look beyond food to consider the possibility that you are having an allergic reaction to something in your workplace or in your bedroom and systematically look to what that allergen might be..
Do you sleep on a down blanket or pillow?