Baby Measuring Big

I am currently 31w4d. We had an ultrasound today and the tech said she was measuring at 35 weeks and was currently 5lbs. Up until now my sonograms have been consistently putting my due date at 5/3. We don’t see the Dr until March 21, but the tech said she looked good, my fluid looked good. I did fail my 1 hour glucose test by 4 points however they said I was only borderline gestational diabetic. Basically I am now concerned that I could go into labor much sooner than anticipated. Has anyone else had this happen? If so, did you go to your due date?