8 week ultrasound measured 5 weeks 4 days

I was so excited to go to my first ultrasound at 8 weeks but we got some concerning news. Turns out we were only measuring 5 weeks 4 days. To start off I had an abdominal US but when the tech said “couldn’t really see anything in the gestational sac” she tried a transvaginal. She still said she couldn’t see much. The tech wasn’t very helpful, I understand she can’t give a diagnosis but she didn’t even offer an explanation of what she was seeing or show me the sac on the monitor, I had to sneak a look myself when she left the room so that I could get dressed again. My doctor called the next day and let me know that based on my LMP, I should be 8 weeks but again, was measuring small so I either ovulated later than I thought or I had a missed miscarriage. I had been tracking my ovulation so I felt pretty confident when I did ovulate because I was able to catch the surge. My symptoms have never been very strong, I was very thirsty and my boobs were sore. Today date, based off of my US I’m 6 weeks 2 days and I do have some mild nausea when I don’t eat in time but I’m just so worried that it’s actually a miscarriage. I go back for an US when I’m at 8 weeks again….anyone else been in this scenario and had a positive outcome? Don’t need to sugar cost things here, looking for all experiences where dating US is off from their LMP.

UPDATE:

Went back for a follow up and the fetal pole never developed. Next steps to be discussed with my doctor. Thanks for all the well wishes and support.