Ultrasound check up

Since having a miscarriage last month, I been getting my HCG levels yesterday every 2-3 days and had an ultrasound last week but it was not visible. I went today and there was the sac and yolk but no baby yet. She said I was about 5-5 1/2 weeks! I was thinking I was 6 1/2 weeks! 🙀 I have another ultrasound next Friday and hoping to see the heart beat and the fetal pole ☺️💜