Why does my mum resent me? and think i'm irresponsible?

hi there, ever since i was in my teens my mother has treated me different from my brothers, i never did anything right, i cant take care of the family dog properly and was always negative throughout my school years but strangely at the same time tried to help me with my maths. Now I'm 27, getting married and i have my own house and job BUT when we got our house she barged her way in to help set it up we didnt have an option even though she was recovering from jaundice and i told her she should rest i was seen as the bad daughter even though i saw that as making sure she was better before taking on big projects...then we decided to get a beautiful dog we even had a name for him but we were seen as irresponsible and she was very disappointed in me as we are getting married and as she said since we could afford a dog we can pay for more of the wedding ! then she made me feel like a small child. and i had to tell the pups owner we couldnt take it as the family would have stopped talking to us!!!! Is that resentment or this my imagination ?