Am I in the wrong or right,

K so my dad has a girlfriend who they’ve been together for 3 years now, her and I do not get along at all, lately i’ve been standing up for myself cause she has gotten to a stage where she is making me feel like shit, saying I’m the reason her and my dad fight when its not. I can’t use certain cups in the kitchen cant eat certain things, like I used custard for my fruit salad and she said that I’m not allowed to use it cause it’s my Dads, and then she gets angry if I don’t use the last of the toilet role, when it’s getting low and it’s nearly the end of role but enough on it for next person I just grab one from ground so I don’t have to change it which I don’t think is bad cause it’s not causing her any harm in me doing it, and then she said if you do it again I’m gonna tell your dad cause thats just pure laziness. And then she been talking to my brothers girlfriend about me, saying how I should be paying rent, even though I’m still in school and Dad and my mum have always not got my bothers and sister to pay rent until they had a full time job in which case I don’t have a full time job, and that I’m not allowed to drive dads car again, and just stupid stuff arrr I am just over it,