Nurse practitioner freaked me out

I had an ultrasound Thursday, saw the yolk sac and fetal pole. Had another ultrasound Monday, the sac grew but she said the fetal pole didn't grow. She didn't seem optimistic she made me feel like this pregnancy is already over. I honestly think my dates are just messed up though. I go back Friday and actually see the dr for an ultrasound. I hope the baby grew and we get to see the heartbeat. I think I'm only 5 1/2 weeks but I measured 5 1/2 weeks last week but the dates don't match, it doesn't make sense. My hcg is doubling the way it's suppose to also. I'm freaked out which isn't good for the baby or me.