6 weeks 4 days based on last period but no embryo

Hi, went and did a vaginal ultrasound today and there was a perfectly shaped gestational sac and a yolk sac and there was a tiny teeny blop like thing that the doctor said she wasn’t sure if it’s the embryo but still really small or not really anything. She said maybe it’s early and am not 6 weeks pregnant and 4 days and it’s too soon. The tiny blop measured at .37cm. My last period was december27th and I ovulated January 10th based on a ovulation kit and cervical mucus. So don’t know if it can be a miscalculation or the pregnancy didn’t complete stopped after the yolk sac. What do u girls think? I am suppose to go again in ten days. Anyone have a similar story happen with them?