Cat does not look pregnant. Can't see enlarged nipples. She is rolling around the floor obviously in pain, making strange noises, raising her back end, there's clear thickish fluid coming out of her bottom, she's licking her bottom and tummy. What is going on?

It sounds like she's in heat. Please get her spayed when her heat cycle is over.

And PLEASE don't let her mate with any male cats indoors or outdoors!!