RH negative with antibodies

Hi ladies, im 9 weeks prego, had my heartbeat apt last week and everything looks great, but got results back Friday that said that i had antibodies showing in my blood.. im rh neg and my first baby/husband are rh positive. i had a miscarriage in april, so roughly 3 months ago, and got the rhogam shot, so my doc said she wasnt worried and thats likely where the antibodies are showing up from. the nurse said they couldnt "titer" the levels bc they were low, and not to worry but theyd draw blood at my 12 week to track the levels. anyone else have this issue? i trust my doc, but cant help to worry.