Ay, totally normal yan lalo na kung petite ka talaga! One of my mum friends din ay maliit ang katawan, and her baby turned out perfectly healthy kahit ang belly niya parang tatlong buwang pregnant lang sa seventh month, lahat ng ultrasound normal, baby movements strong, so kaya lang yan. Siguro yung baby mo ay positioned pa lang sa loob na hindi ganitong lalaki ang tummy, or baka mabilis lang mag-show in the last month kaya don't worry too much. But just to be sure peace of mind mo, check lang with your OB sa next visit para ma-confirm ulit na lahat is progressing well, okay?