At 5 weeks, would explain no heart beat. Your lmp is just a guess. With my self though. With my first two pregnancys my due date never changed based on my lmp. And both babies came on their due dates. And this one (25 weeks now) my due date has still not changed going off my lmp and ultrasounD's. As long as there's no bleeding. Your fine reschedule your apt. .. they should want to see you at 9-12 weeks to give a vaginal ultrasound, and check heart beat
You may have ovulated later than you think even though you know when your last period was. I know that I conceived 2/12, which would make my actual due date 11/4, but based on my last period, my due date is 10/30.
Hopefully they have you scheduled for another ultrasound in a couple weeks and you'll see the heartbeat.
My last period was 14th July and I think I'm only 4weeks so try not to worry until your 12 week scan when you can get a final more accurate dates ect. The less stressed the better.
They thought I was originally 8 weeks based on lmp. But in reality I am just 6 weeks now based on ultrasound. No worries.
My lmp was June 17 so I should be 8 weeks but according to the ultrasound I'm only 7 weeks. So it happens. Good luck I hope all goes well for you.
If the only reason they are saying you are 7weeks is because of your period, don't worry. That's not accurate. You're probably 5w and you wouldn't get a heart beat at 5w.
But if the sac is measuring 7 weeks but the baby is only measuring 5 weeks, that would be a concern.