Confused about my relationship

My girlfriend and I have dated for almost three years. Her parents are in a very well economic condition and bought her a house for her 2 years ago to stay since she was a junior in college. At that point we had been dating for almost a year and I was about to move out of state to get a GRaduate assistantship in a school and get my masters. As she was not comfortable with that, I decided I was going to go to a local school and see if I could find s job to get my masters. she let me live with her for the last 2 years pretty much and all of I have had to do is buy groceries and keep the house clean. I am an international student that my parents do not provide any financial support so all of the money that I have generated has been by working hard on campus. Her parents even let me borrow one of the cars and be in their insurance policy. At this point you might be wondering what could possibly be wrong with the relationship. Living in her house I tried to be the most careful possible to not disrespect her space. It was very frustrating sometimes to clean something and she would make a mess almost instantly and leave it there. in the last months there has been conflicts because she thinks that because I live in her house for free I should buy all of her drinks when we go out and that we need to go on more dates and I have to pay. I believe this would make sense but as my nature I just feel is not right. So yesterday when we were fighting there was a lot of things coming up out of the topic which what the fight started originally. It got very emotional and out of hand. Eventually I suggested how about I pay some of the bills instead because that would feel more right to me. And then she brought stuff like that I always ask her to take me on dates and stuff which I really don't. The fight got so heated up that I told her things that I wish I would have never said to her. I ended up picking my things up out of the house and told her that I could be on my own if she felt she was doing so much of a favor to me. I want to also mention that me living in her house has not affected her financials at any time as she didn't have to pay anything at any point. She just graduated college and she has never had a job before so to me it also feels like she doesn't really understand how much I am working to be able to pay my school, and other basic spendings. I am not buying fancy clothes and blowing money on drinking or drugs. I have about $1000 in my account that I would like to keep for safety purposes and eventually buy my own car if I get a chance. Within the last 3 weeks we have been out partying like 3 times took her on two movie dates and dined 2 or 3 times (sushi, pizza) etc and I paid for everything which I do not feel comfortable with.
Even if the relationship doesn't work again which would be a hard time to get over I would like at least end in good terms as our time was wonderful. Please help me guys I am hurting as I do not know anymore whether I am being cheap for never having anything and now that I have earned something I want to be careful with it although I still feel I do the things she is asking or she is just out of my league for her expectations of life based on her family