From what I understand (and I could be wrong) its not about being o negative or a negative or whatever, its about lacking the
rH factor making you
rH negative. If they had found that your
blood was
rH negative, they would have tested dad's blood too. If he is also negative. No issues. Negative is a recessive trait so if dad was positive, baby would be positive and the difference in you and baby is what would cause issues. Hope this helps a little.