Pop In Vagina

So as im laying in bed i felt a pop feeling in my vagina . I immediately get up to see if it left anything in my panties , hoping my water would've broken or my mucus plug would start to fall lol soon after , buut it didn't .. although i am having some small back pains , mind you im 38 weeks and due Nov 12 .. have any of you ladies experience this and knows what it means or is it just a pop feeling and doesnt mesn anything ?