King of scared... Af lol

So... my due date is May 17th... which makes me 39 weeks exactly tomorrow. And I cant help but think that my baby will get bigger by the time I give birth, when ever the heck that will be. He was already measuring big *2 weeks ahead* so I am so scared that I might not be able to push him out if I go past 39 weeks. This is my third baby and my other 2 were born 6 pounds. This one might be 9 pounds at birth.