First Ultrasound Help

Brooklynn • Due April 2020 🌈 👶💗💙

I had my first ultrasound a week ago and it showed only an empty sac. They said they think I'm earlier than they thought and to come back in 2 weeks. Is this normal? My hcg was also 13000 (this is why I was curious, shouldn't I see a yolk sac too?) They said they couldn't tell me how far along I am. According to my LMP I would be about 8 weeks or so? But they think I ovulated late and weren't concerned. Just afraid when I go back this Thursday if they would still see an empty sac. I'm still having bad pregnancy symptoms, sore breasts and throwing up. I just hope I have a baby in there next time.