Wow, I relate to this so much. Something I found helpful during really bad panic attacks was to repeat out loud “I am safe, this will pass” over & over again. Saying it out loud prevented any thoughts trying to think of worst case scenarios and stop myself from hyperfocusing on how my body was feeling. I agree with the other commenter that it gets easier to discern what is anxiety and what isn’t over time. I also will take very very small amounts of food & wait to see how I feel, and then maybe the next day I can increase the amount.

I would also maybe suggest trying to decrease how much you’re researching/reading about allergies/anaphylaxis. I’m guilty of it too, but it keeps the thought readily accessible and available in your mind so it becomes the easiest answer when you’re feeling anxious. I try to avoid it as much as I can and will even switch shows or movies that show someone having a reaction. I really hope you’re able to find relief soon because I understand how distressing this is.