How to handle this situation with my sister?

I'm sorry but if this is how you really feel then you need to go home. Your sister is paying the rent, utilities and food and all you do is whine. I would be mad too if I worked all day only to come home and find you asleep at noon. Get a job, walk if you have to or go home and further your education. Stop blaming your sister just because she is trying to get you to do what all adults should be doing. And in case you don't know it, you are no longer a child! Apologize to her and go back to mom.