my GF is 8 weeks pregnant and went to get a ultrasound...they tech did what they do and said all they see is a yolk sac and no baby...they also used some "doppler" thing to see/hear a heartbeat or blood flow and found nothing...My GF who is a medical professional said they yolk sac is 250% bigger then it should be at this point and feels like it was the baby behind it and thats why they couldn't see anything...is this even possible??? and if so what are the chances that the tech is wrong and our baby is fine???