Confused….8 week ultrasound

So I went for a scan on the 10th and everything was fine and they saw the heartbeat…..(picture below)

Then today I went for another ultrasound (abdominal) and they said they could only see the yolk sac and couldn’t see the fetal pole and so couldn’t locate a heartbeat. I haven’t had any bleeding or spotting or anything to indicate I’ve miscarried but this Sonographer was also very quick and didn’t seem to zoom in to properly look for something. I have another scan Tuesday but now worrying- can the foetus really just disappear? I’m so confused and worried.