rhesus negative and bleeding advice please

I JUST found out 2 days ago I was rhesus negative and don't yet know the baby's blood type as we are awaiting the blood test results...however....after a little "heavy petting".... I had a tiny bit of red blood when I wiped earlier...literally a few drops and know for sure that it's from the entrance to my vagina, rather than internally or from my cervix....do I need to be worried or get the anti d shot??? I tried calling the midwife and the hospital but the joys of the NHS means I can't get through to anyone on the phone...any advice or reassurance would be great. Thanks x