Question...positive antibodies

Amanda
I had my blood work done this past week and one of my results came back positive for an antibody so they wanted to take more blood to see what it was...it's made me a little nervous...has anyone else ever had this?? My blood type is B- and I haven't received my Rhogam shot with this pregnancy yet and they said if that was it then it would have come back as such. Just worried about the babies