Measuring behind??

Hi! I had an ultrasound today and went in thinking I was 6wks 5 days.. baby is measuring 5wks 5 days. Fetal pole was detected at about 100/102. During the ultrasound the tech told me she could not find a yolk sac. Is it possible to have a fetal pole and no yolk sac? She also said it was hard to get photos/measure baby due to its position. Could that be why measurements are behind? Can anyone share any knowledge/opinions? 🙏The way she spoke to me seemed she was not confident and quite frankly didn’t care to answer any of my concerns nor did the Dr.