Nothing could be more normal than a pregnant stomach, because that's what a woman's uterus was created for.
I suspect that, like many young girls, you have been body shamed and brainwashed to believe that a girl is only acceptable if she has a flat stomach. In your perception, pregnant stomachs have been turned into unfit stomachs, and that brings up all sorts of body insecurities. That's not normal. To see an "unfit" stomach celebrated is disconcerting and confusing to you, and raises the fear that one day you, too, could have a pregnant stomach and be judged by some as unfit.
Yes, I do believe you need help in overcoming your fears. You should be able to view expectant mothers as natural, and not live in fear that changes in your body will make you unacceptable to other people.