Girls, I'm at week 31. When I go to the clinic, I see women on my due …

Girls, I'm at week 31. When I go to the clinic, I see women on my due date and their belly is twice as big as mine, I worry that I have a small belly at this stage, anterior presentation. The doctor says everything is normal. But still, it feels off somehow, soon I'll be giving birth and my belly is small...