5 weeks 6 days U/S

Hello ladies, so o had my first prenatal appointment today and did an U/S. No heartbeat but a gestational sac. I liked the OB, although I felt she was rushing me and didn't to ask her a lot of questions like is their a yolk. The dr. didn't seem concern at all and asked me to come back in three weeks to look for a heartbeat. I though I was 6weeks 1 day based on LMP but theU/S measure me at 5 w 6 D. Anyhow, I can't wait for 12/4 where I can hear the HB. Until then I'm sure I'll be stressing out and reading crazy stories lol. What do you think? Anyone who had a so early U/S. Would love to hear your experiences. Thank you all