please help!! so confused about dates?

Beth • Happily married 💍 Mumma of two perfect little bubbas, Oliver and Evelyn 🦖🌈
Okay so I'm hopeless and I'm feeling so stupid right now. 
My last period was the 23rd November 2016. I had an ultrasound this morning that said I am 8 weeks and 4 days with the due date of 5/9/17.
However I went to the doctors today (due to constipation) and she told me I was 9 weeks and 3 days according to my LMP.
I'm so confused of what I should follow. My gut is telling me to follow the ultrasound cause that measures the babies growth.
Please help???