Science and doctors can only speculate so much, so I wouldn't worry to much about it. I would just eat normally and like others posted, keep active and you'll be fine!
My doctor kept telling me I was going to have a 7 pound baby, well I had a 10 pound baby right on my due date... so if he was off by 3 pounds, maybe your doc is off by a week or so!
Congratulations and take care of yourself, most importantly, just enjoy!!!
