IMHO-You are being taken advantage of. I have a few questions for ya as well OK through out my post. It seems as if she doesn't care and never has. If she did it would have been clean for you before you moved in with her. Maybe she knows that you will clean it up. The question is how long has she lived this way? Some people are set in there ways. If you are raised that way sometimes it's hard to change. Do you live in a Dorm Apartment? Can you request a new roomate? Can you maybe get your own place and get a different roomate? You can't live this way especially if you are a very clean person. It just won't work.
Have you tried to speak with her about it? Does she take your feelings into consideration?
I am sorry that you were kind of put into this situation. I hope my post may help you.