Pregnancy not growing??

Rachael • Trying for our first!!

So I went for a scan when I thought I was 8 weeks and was dated as 6 weeks with a heartbeat...I couldn’t understand these dates but I decided to be optimistic and just be happy we had a heartbeat. Yesterday I had another scan (so a week between scans) and baby has only grown by 3 days? So now I’m dated as 6 weeks 3 days? The sonographer was very confused as she said baby had a strong heartbeat and told us maybe baby is just going to be a small baby???

I have to go back in another 2 weeks to measure again but I’m so worried this is a sign things aren’t right. First the dating 2 weeks earlier than I thought and now the lack of progress? But the strong heartbeat gives us some hope?

Pregnancy can be so cruel, I just want to know so I can either grieve and attempt to move on or if I can relax and enjoy this pregnancy.

Thank you for any help or advice :-)