oh i know how you feel, with all three of my Bubs i was constantly being asked if i was carrying twins and bets where on that i was.

I just had to deal with the fact that when i am pregnant i carry alot of fluid. My babies have not been what i would call big 7lb ers. Yet i was massive. Hun we are all different and all carry bubs differently. Try to just enjoy your growing bump and pregnancy. Just tell the oh so annoying people that you noticed they seemed to have put on a bit of weight lately too........ that will shut them up. I just used to say yep i growing a super baby.
Congratulations on your pregnancy