Why is my baby bump look so small

Mummies, I’m kinda of worried that my baby bump look soo small which doesn’t look like I’m pregnant at all. I am 20 weeks and 2 days but I don’t seems to look pregnant at all. I don’t have any symptoms such as stretch marks or any back pain or leg pain at all. I am worried as well that many people will thought I’m lying abt my pregnancy. And how to know if my baby is healthy??? Help me out mummies.