Advise plz

You'll get a better dating at 12 weeks, it's hard to get a proper measurement when you are early. 🤞 For you though

But going of period should be 9 weeks pregnant

You may have ovulated later, as even though they class you as 4 weeks pregnant when you find out... You are technically only 2 weeks... As you ovulate around 2 weeks after your period ends and then can take a week or 2 to implant which then takes 48 hours to double and be enough to show on a test... Its awkward so you could be a week or so behind depending when you ovulated/implanted x