Date wrong or Big boy? That is the question!!

OK so this baby is going to be big I guess or he has gone thru one heck of a growth sprut recently. I am measuring 4 cm to big so thru u/sound last Thurs. it looks like he is very healthy just big so far. I have gained weight on target so not sure what is making this baby so big but at almost 32 weeks he is weighing in at 5lbs 6oz give or take. Yes, that's large. The Dr. thinks my date may be wrong but cant say for sure so I just have to be ready for a baby from mid March on or the possibility that he could be huge and have to be induced or have c-sect. if so. Will know more after next u/sound on 3/5. I sure hope he slows down a little. I'm taking it easy as baby is head down and causing me alot of pain with walking already and some contractions. The pain you endure for your children.