Felt a Pop

Yesterday i felt and heard a pop right on top of my vagina. Haven't really noticed any leakage but I already have a lot of discharge. No cramling either...I am 35 weeks and 4 days, anybody else experienced this? I'm just waiting out. I did earlier this week go in for NST because baby had decreased movement by like 70 percent. They checked her heart beat and movements and she was good and ultrasound looked good as wel. Ever since she's moving a ton.