lower uterus suddenly?

So i am 34 weeks today, and i swear my uterus is suddenly lower. usually it is above my belly button and fairly round... now when i am lying back it's clearly below my belly button, and now it's almost like it's stuffed DOWN! Possible dropping? This is my third pregnancy and my belly was WAY rounder the last two times (both girls... and this is a boy! maybe that's why lol)