Ultrasound at 5 weeks with empty gestational sac

Hi everyone. I had a transvaginal ultrasound today at 5 weeks 2 Days. I was being treated for infertility so my reproductive endocrinologist follows me closely. My scan showed a gestational sac but no fetal pole or yolk sac. My doctor is very confident that this is normal and too early to see much. She said it’s good we see a sac in the uterus. My Hcg has been doubling normally. I’m just so nervous about this. I have another scan in a week and am worried. Any one out there have a similar experience and go on to have a healthy pregnancy?