Worried

So had my first US this week at almost 8 weeks based on LMP and the tech could not find the baby over the tummy. So had to do vaginal, and baby showed up right away but the size of 6 weeks 1 day. I knew I wasn’t 8 weeks based on the day I ovulated and the day I know I conceived. But still should’ve been almost 7 weeks not 6 weeks and a day. Should I be worried?

We saw a heartbeat, the baby is in the right place so I was happy! But will be going back in two weeks to do US with the doctor again.