What Causes Thick And Numb Vaginal Walls?

Hi, im 22years old and had my 3rd child 5months ago. I have had regular periods for the past 3months until this one. I was on for 2 days, off for 1, bk on for another day and now im off. This sounds silly but i wasnt sure if i had a tampon in so i checked and i thought i did so i tried pulling it out and i realised there was no string, it was the wall of my vagina that has thicken and completely numb is that normal?