Elective Ultrasound and baby “looks small”

Hello all, I went for an elective ultrasound to hopefully hear my baby’s HB as my first appointment isn’t until 10 weeks. Based on my LMP I was 8 weeks and 1 day. Well the lady said she couldn’t measure the baby but it definitely looked smaller than 8 weeks - more like 6 she said. We saw the HB flickering but were unable to hear it. I have been crying nonstop. Is this bad news? Has this happened to anyone before? I called my doc and they ordered progesterone and HCG levels but I haven’t gotten the results yet. I’m totally freaked and having trouble functioning. Anyone been through anything similar? I don’t think my dates are off as I literally got a positive test on day 28 of my cycle. Any help would he appreciated!