Rhogam

At my next appointment, I have to get the Rhogam shot. I'll be 28 weeks. I received Rhogam once before after a miscarriage. I have fretted about EVERY LITTLE THING during this pregnancy. I am a natural worrier as it is, but I just want my son in my arms so badly, and I want to do everything right by him. I know that if I don't get the injection, my own body could potentially harm my baby. My question is, can the shot itself be harmful? I've read conflicting things thanks to Google (the internet can be so scary!)

Thanks in advance for responding!