Confused

Had our first prenatal appt yesterday. This is my 2nd pregnancy and according to my lmp I should have been 9 weeks. Everything went well except when it was time for the abdominal u/s. I had what my midwife called a beautiful yolk and gestation sac but she could not see a fetal pole. She told me it's 50/50 at this point:/. We go for an internal u/s in a couple days and we are praying we see our baby. My CNM said I'm either earlier than thought or it's a blighted ovum but she's never really seen one with a yolk sac. Could baby be hiding?  I can't see me being 6 weeks vs 9?  Also my hcg level was 21869 today. Im very, very nauseous and have a bump.