Hello, My 2 Year Old Son May Have Been Given

Hello, my 2 year old son may have been given a duplicate vaccine (Hep A) within the past 3-4 months. We transferred pediatricians and there was no record on his current immunization (provided to new pediatrician) of the last shot he received this past May. Dad and I were both there so we know he received a shot. Anyway, went in to new pediatrician for other concerns and they said vaccine was needed. If he had this shot twice, I want to know ANY reactions or concerns there should be, as he has been "off" since the last vaccine this week, which I chalked up to be him just getting a vaccine, until I came across these records. I have already contacted previous Dr to verify, but they have yet to return my calls. Any literature or response is appreciated! Thanks!