Miscarrying ???

I had an hcg on wed showing 2233 at 5 and a half weeks and Friday it went down to 2101. Dr. says this doesn't look good. He ordered an u/s and there was a yolk sac and amniotic sac but not a fetus. He said there was a very small chance that it was too soon to tell on the u/s, but that it would most likely end in m/c because of the blood work. I go to get my new hcg's on Sunday. I'm a wreck and not sure how to handle all of this. Any advice? Any positive outcomes from similar situations? Any chance this is a horrible fluke false lab reading?

Thanks,

Jill