Went for my ultrasound, couldn't see the baby! Advice please 😔

I went to get my ultrasound today, and glow is saying I'm 6 weeks and 1 day. But we could only see a gestational sac, but no baby, and it measured at 5 weeks 3 days. She said this made sense because it was so early, and has me coming back in two weeks.

I have had my blood drawn, and it's being tested to see that my hcg levels are multiplying as they should be, won't know til Wednesday.

Anyone had this happen before? What happened? I'm feeling very scared and just want to go to bed 😔