not growing?

I feel like my belly hasn’t grown very much at all for at least the last month or so. I’m 30 weeks today, my last appointment was at 28 weeks and baby was measuring a week behind but the midwife wasn’t concerned, the baby has always been measuring to the day before that, my next appointment is next week and I’m a bit nervous that maybe my baby isn’t growing they way she is supposed to? The top photo is 30 weeks and the bottom is 26 weeks. anyone else feel like this? I’m sure everything is fine but I can’t get the thought out of the back of my head.