Possibly miscarriage?!?

I went in for my ultrasound i was supposed to be 8wks 5days but baby was measuring 6weeks and sac was 7, no heart beat was found but told me to come back in two weeks just to make. They talked to me as if they didnt think i would have a heartbeat and i would be miscarrying... I have carried/birthed two babies already.. Anyone have any similar story? I am just at a complete lost right now. ☹️