No fetal heartbeat - ultravan show 6weeks 2 weeks ago but tranviginal scan show 6 weeks today.

Hi all, need your advise. I went to see gynae 2 weeks ago with ultrascan it show that my gestational age is 6 weeks plus… went for ultra scan yesterday gynae say not able to detect heartbeat and refer me to do transviginal scan , report came out my gestational age still 6 weeks and no fetal heart pulsation. What does it mean? Does it mean that the baby is no longer growing ? Is there any possibility that heartbeat will be detect later? Based on LMP, I should be 9 weeks plus. I had miscarriage once last year so I’m kinda worried it might happen again. #advicepls