18w pregnant. used same knife that cut fully cooked cheeseburger 4 mayo. still using mayo. now worried. will this make baby sick?terrified of listeria

Listeriosis: It is unlikely that you will acquire listeria infection in the manner in which you have described, and this is not likely to be making your baby sick. Pregnant women: typically experience only a mild, flu-like illness with listerial infection, but if it occurs they and the baby can be damaged, but what you describe is not a likely scenario.