If you have RH - blood did you receive the Rhogam shot?

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I have A- blood and my doctor wanted to do the Rhogam shot at 28 weeks. I'm 27 weeks and had spotting last night so they told me to come in and get it done early today. I did because of the spotting but after I had it I went home and was so tired I passed out for 3 hours and I don't typically nap. I still don't feel right. Are any of you ladies getting the Rhogam or did you refuse?