It's definitely not anything to stress over, especially if you're keeping up on prenatal visits and the doctor hasn't seen anything of concern. I carried my son in a transverse lie, so he never really showed very much at all, and actually showed LESS after he dropped down right before he was born. I felt huge because he was tucked up under my rib cage instead of taking up space in front, but after he was born many of my co-workers couldn't believe that I was already on maternity leave, they thought I couldn't possibly have been more than four months along! He was born right on time at 8lbs 9 1/2 ozs, so it's not like he just didn't have time to get big. I'm now 5 1/2 months pregnant with my second one, and am only now showing enough that the people who know me can tell that I'm pregnant...and those who don't think I'm just a little overweight.