My mother thinks i prefer my father.

because i told her that i think im not gona be as financially supported as my sister is. By financially supported, i mean my father being able to pay dor a new car for her , all her studies and the place she stayes. I told my mother and sister that i feel that my oppertunities are fewer than my sister's because my father recently quit his job. My mother  took it up like i said she is only in it for the money with my father and that she is selfish, wich is totally NOT true and NOT what i said. I guess i probobly did say SOMETHING wrong if she took it like that? I know that i need to choose my words precicy in order to get my message through. I only wanted to express my concerns , not point her out and offend her... But What should i do, why does she feel like this? How do i now handle the situation?