what does uterine stretching feel like?

Okay ladies this isn't my first rodeo but I haven't been pregnant in almost a decade! My children are older, so I'm having trouble remembering. I'm 16 wks 2 days pregnant. I'm not having any pain or bleeding whatsoever. But I feel almost like a very light "throbby" feeling in center of my uterus. Not contractions or BH but almost a sore feeling. Idk how to explain. Not round ligament pain. Just a very vague feeling. Wondering if it's just normal "growing" . Just had appt Friday and everything looked great and heart rate great