Someone tell me it's ok.

My son is 20 weeks yesterday.

Will be 5 months on the 24th and he has still only rolled over once like a month an a half ago. He does not like to be on his stomach very long and moans and growns till he starts to cry.

He's 28 inches and just over 20 pounds I don't think that matters but maybe someone else has a lazy chub? He loves to be sitting (assisted) but put that boy on his tum and be ready for a complete mood change. I feel like he's behind. He was taken at 37 weeks of pregnancy due to a previous stillbirth 12 months prior to his birth. Idk if him being born a little early could case this delay, is he fine or am I just a complete nut case??? Lol