Punch,pop,kick what is it....

Even though I feel as if my questions never get answered

ill post in hopes that maybe just one person can help...

Ive never had this before....but my baby is head down etc and im 37+3 :).But basically only when I go to pee(those little drips of pee) I get punched or have a popping kind of sensational...It doesn't happen unless I pee...nor has it happened up until now....ive been having mild cramps at night but nothing to be bothered about....but does anyone else get this?Its really a weird popping punch feeling but she is definitely head down etc...help please :) Its like being kicked...except...her leg isnt there...