Does my cat need to see a vet??!! Please help!!!?

About 30 mins. ago I noticed my kitten's rectum looks like it has popped inside out (it's sticking out maybe 1/2 an inch) like maybe she strained too hard and popped something. she's eating and playing as usual and doesn't act like it bothers her, but I've never seen anything like it, although I've heard that cat's with no tails (like mine) can have bathroom problems. all the vet offices in town are closed until Monday. does anyone have any idea what this could be and if it is fatal?