5 weeks 6 days and can’t see baby on the ultrasound

this is my second baby and my level is at 810. I read that it’s usual to start seeing the baby when your levels reach 1000... they said they saw something that might be the sac but they’re not sure. they’re having me come back in in 2 days to do a repeat ultrasound and hcg level check.. has anyone else experienced anything like this? I’m so worried and have been crying on and off since they told me that the ultrasound was inconclusive. please help ease my mind.