Belly flattened out?? A little scared here...

Be
My belly has flattened out overnight!! The left was 36 weeks exactly and right is 37 weeks exactly. Could my water have broken and I not noticed thanks to my long baths? I have already had my bloody show (I hate that term - nasty), lots of cramps and contractions, though nothing regular. I noticed even before I got up this morning that it was flatter because I can feel my skin is way more slack. This freaks me out a bit!! I've also started having complications with preeclampsia if that makes a difference. Help ☹️️