I live with my sister and it is horrible. Will I be better off on my own soon?

She just started this crap about how they pay 4/5 of the rent and I pay 1/5 so I am the minority. (They are my niece, my sister, my nephew and my niece.) I am also not allowed to put my food in the refrigerator or the cupboards or they will throw it away or eat it. And they will not give the garage door opener because she needs to supervise what I do. I pay for the garage in my share of the rent. In addition she says she needs to control me because she is more mature. I am 45 and she is 47. I told her she is not my mother and she died 8 years ago. She replied with and I am glad she died because treated me like ****. My lease is not up until August so I am stuck how do I survive until then? And for Christmas she invited a bunch of people over one of which owes me $300 and she stated I needed to bury the hatchet with her. That is not her decision to make and the last interaction this girl and I had she called me a ***** and said I should burn in Hell. She offered my bed to some of these people because I am quote supposed to accomodate them as this is Xmas and is the thing to do. I think my sister needs major medicine and mental health assistance big time. How do you handle crap like this without going complete nuts?