My baby's body is measuring almost 3 weeks ahead but my belly is measuring really far behind

Hey moms, I am in need of advice and to understand maybe alittle better about these measurements. So I went in for an ultrasound at 26 weeks his body was measuring ahead of his size for example his limbs were around 3 weeks larger chest and head circumference around 2 weeks. I get that can happen but what worries me is my belly measurements they did showed I am only 19 cms from the public bone to the top of my uterus. I can feel him actively kicking stretching etc all the time but I just don't really know what to expect from this information. I have an ultrasound technician that does anatomy and then the docotor that does my regular checks. I didn't really get a proper answer about these measurements and it seems like I am just a number when being seen so I am a little confused and worried. Can someone explain what is going on with my stomach?