Confused 🤷🏼‍♀️

So my DD got pushed back due to baby measuring small. I switch my DD in my <a href="https://play.google.com/store/apps/details?id=com.glow.android.nurture">pregnancy app</a> and it tells me I got pregnant in week 2 🤦🏼‍♀️ also this doesn’t add up with anything. I don’t know if my baby is just a small baby because they grow at different rates or what. What are your opinions?