I'm confused

Alexis
Ok so all my apps and even the receptionist at my dr when I called said that I was 4.5 weeks when I found out... but I'm confused.. how?? Because the first day of my last period was April 2nd and today my app says I'm 5 weeks.. but my iui was done only 2.5 weeks ago.. so wouldn't I only be like 2.5 weeks pregnant? I'm just very confused?