Quick question! Please read!!

So I was asleep about oh... 12am and i guess i stretched my legs straight all the way down, and my pelvic/pubic bone? Popped soo loud! It kinda hurt a little but not alot. Enough to wake me up! The noise and feeling both woke me straight up. It was weird and never happened before. Now my pelivs is sore but im not in terribleeeeee pain. Is this normal?! it never happened with my first! Im also a bit crampy this morning now in my tummy... And my inner thighs Feel achy...

EDIT** Baby already dropped into head down position weeks ago