JP-dont worry about big babies

Unless you have something like GD, your body will not produce a baby bigger than it can birth. My mom had 5 babies naturally and she said her 10.5lb was the easiest of em all! (she had untreated GD, but she still had only a 2 hour labor from first contraction to placenta-at home, unassisted-none the less)
Also, the average American baby weighs 6lb-9.5lb so an 8lb would be smack in the middle

From here on out the baby isn't going to gain insane amounts of weight. It usually begins to stay consistant.