Should I be worried?

Based on my known date I'm about 6 weeks...last week my hg levels were only in the 500 and they only saw a line on the ultrasound sound. Today my numbers were around 10k but they only saw a sac nothing in it. They think I'm just earlier than I think I am and I'm going back in Friday. I'm hoping for some good news and we see something and it is just earlier than I thought. Can I get some good vibes and. This is my first time and I'm so scared is it likely it's just I am early or is something wrong?