I forgot the allergy note on the school trip form

Dear Delyara, I am an administrative assistant at a primary school. A child has a severe nut allergy. His emergency plan is clearly documented, but when I prepared paperwork for a field trip, I copied an old meal preference sheet and missed the allergy note. Another teacher caught it before lunch was served. The child was never exposed. Nothing happened. Everyone keeps telling me that. The headteacher reviewed procedures and added a second-check system because relying on one person is unsafe anyway. I still cannot stop thinking about what might have happened. I know this child’s mother. She trusts us. I see her every morning. She does not know about the near miss because school leadership handled it as an internal safety incident with no exposure. I have begun checking every medical form repeatedly. My colleagues say I am becoming obsessive. Yesterday, I stayed an hour late comparing two lists that already matched. No child was harmed. Yet there is a version of that trip that exists in my head where one forgotten line becomes an ambulance, and I cannot persuade myself not to visit it.