Different women carry differently. Some look big, some don't. I don't think the size of your belly really indicates whether or not the baby is healthy.
I was huge with ym second PG, and I remember about two months before I was due, my SIL told me, "you are never going to make it to term, you are so huge!" Nice! Give me something else to worry about, since my first was a premie.
I made it to term, BTW so nanny nanny boo boo!
Denae