Baby not rolling over should I worry?

My son just turned 5 months and is not rolling over from tummy to back or back to tummy. At two months he was rolling over tummy to back but just stopped out of nowhere. I do tummy time all throughout the day with him,

I try and encourage him with toys I don’t understand why he just stopped. Should I be concerned? I just see on here so many moms babies are advanced and like sitting up by now and makes me feel like I’m not doing enough :(