So lost

Heather • 10 year old daughter. Currently TTC.
When I had my pregnancy confirm appt the dr told me I was 8 weeks. I went today for my ultrasound and they couldn't find the baby. They told me my hcg levels dropped and it could be that I am just really early in the pregnancy. I am terrified. They said they will have my blood work results today.  Has this happened to anyone?