ER ULTRASOUND BABY WEIGHT

So yesterday I went to er because of a flank pain I was having/still have on the right side of my rib that won't let me do much. They did an ultrasound of the major organs on the right side under my rib cage. Everything came back normal and they couldn't find a reason as to why I have that pain. Anyways they also did a regular ultrasound and once I received the results stating that everything was normal and she was perfect. Found out she's weighing in about 1376grams which is about 3.03lbs and measuring a week ahead. I have no GD so it's crazy. She might be a big girl. My son was 8.4lbs at 40w5d. So scary to think she might be bigger. On another note haven't gain as much weight as I did with my son, so who knows lol. What's everyone's baby weighing in at?