No heartbeat at 10 Weeks 😕

We went to the doctor yesterday for the regular check up. I am 10 weeks exactly and while i was having the ultrasound my doc became quiet and told me that at 10 weeks one would normally see a heartbeat, but there was none. The embryo was 4mm yesterday. When it is between 3 and 5 mm a heartbeat should be there. I have to go to the doc again on tuesday since it should be 7mm big then. if there is still no heartbeat it is a loss.

Now i am worried. Has anyone been in the same situation and everything turned out fine?