anyone with rh-negative blood type?

I had my second doctors appointment on December 13th. We should have been reading 12w2d but we were told our baby stopped growing at 12w. I took the medicine later that day and went through the worse of the miscarriage later that evening. I stopped bleeding around 3 days ago. Anyways, they never did blood work until last week. I got my results back and was told my blood type is rh-negative and have to go in and get a rhogam shot at my next blood work (which is Tuesday, so a week later. I go back every week until my levels go down). I read online that they are supposed to give these shots after 72 hours of a miscarriage. This is my first pregnancy (we don't plan on trying anytime soon but I'm worried about being rh-sensitized) and just wondering if anyone has gone through this??