I'm sorry, my baby is how big?

Ben and I went to the Dr. yesterday to have an ultrasound and see our baby! We were so excited and curious about the size of the baby. I have been feeling him all over, but know that he is quickly running out of room. When I was pregnant with Sam I asked to be induced at 38 weeks. At 38 weeks Sam was 9lbs 4 oz. I asked my Dr. if this baby would be that size at 38 weeks. He said probably bigger. Yikes!
So I am currently 31 weeks along. I have 9 weeks left in my pregnancy. My Dr. told me that babies at 31 weeks weigh 3lbs 13oz. Well our baby is 4lbs 9oz at 31 weeks! The baby will continue to grow an average of 8oz a week from here to my due date. I am glad he is thriving, especially since I keep getting head cold, ear infections and the flu this pregnancy. I am excited to have a big baby again, they sleep well, feed well and I dont feel like I am going to break them. Ben did the math, because he's a genius, and told me that the baby will be around 10lbs at 40 weeks. Yikes. I hope my body can handle that. We didnt get any great pics from the ultrasound, this is baby's ultrasound pic when we found out he was a boy. Baby was so smashed in there he had no room to move or wiggle. However we were able to get a few measurements. His head is HUGE, nice round Charlie Brown shape, his thigh bone is 3in long and his spine looks very nice. Kidney's are great, organs looks good, the Dr. said he looks wonderful. I cant wait for him to come. Harrison is so excited and asks me everyday "are we going to the hosbitable to hav a baby today?" He's always very sad when I say no. Sam is in denial or his typical state of I dont hear you, I dont know what you are talking about, let me change the subject. We'll see how that goes. Ben and I are excited and cant wait to have another boy around here.