Confused! 🤔

Ol

So my due date by calculating was 31st Nanuary! I gone 7th week scan and they said due date 2nd February and today I went in today when I thought I'm 14.6 weeks they told me I'm 15.5 days! And my due date is 27th January !!! Wth!!! I'm very confused ! And I don't know when is my due date !!! :( what date shall I think omg