When did you start to show?

I'm 18 weeks and 5 days, and apparently im not showing at all. I'm a little heavier (153 pounds and 5'1) but during this pregnancy so far I've lost about ten pounds and only recently was told I gained a pound and a half. Everyone is starting to make comments about me not showing, asking if I'm even pregnant or just lying, and asking if I'm actually ever gonna show. It's getting really frustrating, there's a coworker who is due the day after me and she already shows (this is her third and my first so I understand why she would start to show before me) but anyway, when did you ladies start to show?