Rhogam shot didn’t work?

I have a RH- blood type and my husband is a RH+. My antibody testing came back strange and was sent for more testing. Turns out the titer for my antibody is low and the baby almost certainly has a RH+ test and is now at high risk for hemolytic disease and I’m supposed to get titer tests done until I deliver? I’m almost 38 weeks pregnant and this was found as a complete fluke last week while I was admitted for preterm labor. I’ve asked my doctor explain the results to me but they just keep saying “we will discuss tomorrow (at my appt).” Of course I’ve been on Google and it sounds like all of this means my rhogam didn’t work. anyone have any experience with their rhogam shot not working?