CRL measurements - only 11mm in 2 weeks?😔

[SunnySideUp2020]

I am BF and have irregular periods. I got my first positive test at what I think was 8 or 9 dpo based on my last LH surge.

Since my lmp is not reliable I had to go for dating scan 2 weeks ago and doc said I measured at 7w2 CRL was 10 or 11mm. Heartbeat was strong. I thought it was a bit weird because of when I got my first positive pregnancy test would have been like 4 dpo... but trusted the measurements.

Today, so 2 weeks later, we measure again and I am at 8w6 CRL 21mm, Heartbeat still strong.

So in 2 weeks it haa growns 10mm not the 14mm google suggests (1mm a day) and I went from 7w2 to 8w6.
Very weird. And i am a bit worried. Had a miscarriage before and was naively thinking the measurements were a bit off but all is good.

The new date of 8w6 corresponds spot on to my original calculations though.

So i Dont know if I should prepare for the bad news or it's just his first measurements were a bit off...

Anyone been in a similar situation?

Thank you

The baby has grown absolutely fine! If you think how tiny those differences are it is very easy for a scan to be out. And when they're dating you they're going off average sizes at that gestation. It's not an exact science. I've had 4 scans and been given a different due date at each one. Babies can grow at slightly different rates. In the kindest way - step away from Google!