I’m so confused

So I went to the hospital for spotting. They said they picked up 2 very low heart rates and want me to go get another ultrasound on Monday. Which I am but my ob said I’m early and on threatened miscarriage risk. I’ve had 3 other kids but idk what I’m looking at. Like idk I don’t see twins. Also it only says baby. Like they were in a rush and told me they couldn’t do much but I’m still confused.

Help?