Ultrasound

Has u/s yesterday and couldn’t see heart beat. I was so in shock at seeing baby that I don’t remember what the tech said lol. But my husband said that he believes the tech said that the line on the baby is the start of the heart forming?? And that it’s still a little to early to see it beating. Does anyone else have any experience like that and confirm that that’s what it is. I don’t know where else the hubby would’ve gotten that information lol I also seen a nurse practitioner and she said that I should be 7 weeks today but the tech is thinking more like 6 weeks