Cystic space during ultrasound

I went for my first ultrasound and the Gynae said could not detect any gestational sac or yolk sac. As per calculated by last period I was suppose to be 5 weeks. Doc said might be too early. But in the ultrasound, there could see a cystic space. Did anyone experience that? Does the cystic space means a baby is forming soon? Pls advice #firsttimemom