I would like to know who has dropped their belly at what time frame? I…

I would like to know who has dropped their belly at what time frame? I have only one week left, but my belly hasn't dropped yet, and there are no premonitions, just that it's hard to walk far and shortness of breath when I walk and talk. And it's also unclear how they count me according to ultrasound, I am 39 and 2 days, according to menstrual cycles 38 and 6 days, and according to fetometry 38 and 2 days. How did you experience this?