Heartbeat then no heartbeat

This might be a little too farfetched but I'm trying to be positive. I was scanned today (abdominal) and the radiologist said that he was doubtful about the baby's cardiac activity. My gynaecologist recommended that I wait for another one to two weeks. According to my LMP I'm 10 weeks and 4 days pregnant but the baby measured 6 weeks and 4 days. The initial TVS that I had gotten showed that the baby had a perfect heartbeat and measured 7 weeks and 4 days (this was about 2 weeks and 3 days back) Is it possible that the baby's heartbeat goes away then comes back somehow? This might sound really stupid but I'm trying to grasp to whatever I can rn. It was undetectable on the same TVS machine this Friday and that doctor advised for medication. Please note that I have not spotted or bled (I'm also on extra progesterone). Please share if you went through something similar. Need to be positive right now.

Edit: we had been trying for 3 years and it was the first time I got pregnant. Male infertility factor.