Worried

Ashlee • Sat, Mar 11

I had my ultrasound yesterday. The tech said I was roughly 4 weeks he saw the gestational sac. But did not see a yolk sac or heart beat. When I went to the doctor Monday my HCG levels were a 828. So my doctor thought I was 5-6 weeks. Is it normal not to see a heart beat or yolk sac this early?