.....because you're huuuuge!
I heard this all through my first pregnancy and at least 3 times a day with dc2. I have always measured spot on and am pretty tall so mainly look all bump.
I know people aren't being nasty but come on people, what response can I give? "It's its not twins" "I am huge aren't I...except I'm not I'm 7 months pregnant and this is generally what women who are 7 months pregnant look like".
It's wearing me down...okay rant over.