Nervous

I got an early ultrasound at what I thought was 6 weeks 4 days. They were unable to see a fetal pole or heart beat but did see a gestational sac and yolk sac. They measured me 6weeks 1 day and both the ultrasound tech and doctor said it could be just too early to see anything else. I have seen so many people post about early ultrasounds on here with a heartbeat so I am of course disappointed and anxious that I didn’t have the same outcome. Did anyone else have the same experience with a positive outcome? I have a repeat ultrasound scheduled in about 2 weeks and the doctor said she is “cautiously optimistic” but I can’t stop worrying about it.