Maybe a fetal pole?

Went in for an ultrasound at 6 weeks 5 days, they saw the sac and yolk sac but no baby so they scheduled another ultrasound for 2 weeks time. I had some blood work done and HCG is measuring normal. I had another ultrasound today according to my period I should be 8 weeks and 3 days. They saw something that wasn’t there the last time which they thought might be a fetal pole but they could not determine 100% At 8 weeks should I not be further along? Is it possible I am not as far along as I think I am? I have to wait two more weeks then go back again. Feeling nervous