confused about due date

So every since the beginning I have been confused about my due date. My first day of my last period was June 3rd. So that would put me at 37+2 with my due date the 10th of March. However every ultrasound that I've had I'm measuring 10 days behind, so they changed it to the 20 th of March basically saying that I've must have had my period dates wrong (ugh which I don't)
Anyhow, I like to think that I'm 37 weeks and is prepared for the 10th, but I could also only be a little over 35 weeks. What do you guys think? It feels like I'm going backwards instead of counting forward. And I have no more ultrasounds scheduled.