Should I be worried?

So I feel like my belly has just stopped growing... at my Drs my belly had only grew 2 centimeters in 4 weeks I also had heard that your belly should be about the same centimeters as how far along you are at my 28 week appointment I was only measuring at 27 centimeters which was only 2 centimeters from my last appointment... I am almost 30 weeks and just feel like I've been the same size since 27 weeks I also feel like I haven't "popped" like everyone says they do