Any advice and prayers would be extremely appreciated!!!

So I had my first appointment today thinking I was 8w6d and turns out I’m only 6w2d. Baby’s HB was 120. My Dr told me everything looked fine but the only thing that was a bit concerning was that my amniotic sac is measuring smaller that it should be and that would put me at high risk for miscarriage. I go back on the 27th to check on baby. Has anybody else experienced this? If so, how did it turn out? Any advice would be very helpful!! I’m freaking out.