I can relate to what you say and my mother too was fond of changing her idea about me back and forth. I noticed that both of these feeling were shallow too, both her love and hate never seemed to be deep or meaningful, it seemed she said both things depending on how she felt at the moment. That she spoke of love and hate as if they were simple shallow emotions. I am curious as to whether your mother was the same way?
I'm quite sure my mother has histrionic P.D. (with some traits of borderline and narcissism). I can't imagine how true feelings could ever change that quickly without a reason. I guess she did it all for the drama. All her life is playing different roles. When I was a child she played the role of the overprotective mother. I think this is impossible to be true when I see how few she cared about me later. I was close to stopping with my study because of her. And after that she didn't talk to me for a whole year. I can't take her seriously anymore. Our relationship is just one big farce.
She treats all people like that. Most people like her at first, but she split with all her friends and partners (don't ask how many) after some time(of course it's always their fault, she's just the victim).
When I was a child I thought she was the normal one, so I had to be a very bad person, upsetting my mother like that.
I think I never truly loved or hated any person. I never express strong feelings. My mother uses emotional expressions to get what she wants.