I'm preparing to take another IgG4 blood test for delayed food allergies. Yesterday I ate a little of many of the foods that are on the list that will be tested then did some shopping. Felt bad so rested in bed. Blood pressure dropped to 71/48 with 108 pulse. Allergic reaction to the foods? My normal pressure is around 120. Known allergic to gluten and more but this low blood pressure from food?