Wrong due date??

I have a question that might be stupid. 3 weeks ago when I went to the doctor I had a growth scan. I was 28 weeks pregnant, but I saw on the screen that she was measuring 30, but nobody ever said anything about it or seemed concerned. I was thinking back last night and my last period was January 27. I’m thinking that I conceived February 9. Based on my last period and the growth scan where it said she was measuring 2 weeks ahead, I am feeling that I may be farther along than what is thought. Instead of being 31 weeks, I feel that i’m 33. Has anyone ever ran into this? How did you mention it to your doctor? Did they change your due date?