I wouldn't worry about it. From, what I heard its not very accuret. My doctor told me that my son was about 7.5 lbs 2 days before I went into labor. He was born at 9lbs 11oz! All natural, no pain meds. You will be ok
A fundal measurement is not very accurate of baby size and +/- 2 cm is considered normal. I wouldn't worry about a big baby just yet