Peanut butter

Riss
So when I was a baby I tested positive for being allergic to peanuts. This has never affected me. In fact, I love peanut butter. I noticed last week that now when I eat peanut butter I get really itchy. This has never happened before. I am 21 weeks pregnant and today I wasn't thinking about it and ate a Reeses cup. I got itchy again. I am extremely worried now that my baby is allergic and that by eating a Reeses cup today, I hurt her. Should she be ok or should I go see my doctor? I would base it off movements but she is so unpredictable.