16 weeks. Still no bump. Lost 10 pounds. Hard to gain weight.

Basically the title says it all. I’m not showing at all, which is depressing. I’ve lost weight due to being sick (which has eased off ALOT in the past week) and well I don’t know. I feel like this is unhealthy and as if baby should be making its appearance but I don’t seem to be growing at all. Should I be worried