I measured a week further ahead going by my fundus measurements as well. These measurements arent very accurate at all and all doctors measure differently. Even the ultrasound you get is not that accurate. The very first ultrasound you have is the most accurate as far as dates are concerned. My bub ended up being 10 pound 6 oz and 60 cm long. My doctor never once said he was going to be big even though I was huge!! I attempted to have him naturally but he was trying to come out with his hand up near his face and was stressing so in the end the best decision was to have an emergency caesar. The doctor later told me that if he hadnt of been coming out in a difficult position that I would have been able to have him naturally and that even being big he still would have fitted. Dont worry about it, I am sure it will all work out for the best. Go with what you think is best!