I need assurance...

Aerial

I’m 9 weeks and 5 days today. We had an ultrasound not too long ago and they said everything was perfect and the baby had a strong heartbeat. I went back today and he used a portable thing to try and hear the heartbeat. I couldn’t hear it but he said it was there. He said that was normal for how early I am but it still worries me. Has anyone else had this happen?