Starting on Sunday I started getting red spotting that persisted into Monday.  On Monday i called my doctor and they sent me to get blood work.   I found out that I am O negative and that my body was attacking the fetus.  I'm 5 weeks today and just got the Rhogam shot this evening.  I'm really worried that it's too late for the Rhogam to be effective.  Has anyone else gone through somethig similar?