Scan went wrong ?

I had my first ulrasound today and the technician said she could see a tiny sack and that it was really small so she couldnt tell if there was anything there- but i should be almost 7 weeks so i am so confused- she said i looked 5 weeks- so hell early. Please tell me this has happened to someone else and it all turned out ok. I am terrified!!! ?? i tried to get my blood results back and they were still working on them so i dont even know if they came back positive or not!! I cant stop crying it is horrible!