I dont feel connected to my family in any way

I know today is Mother's Day and part of me still feels some guilt for not doing anything for my mother even though she has been a shitty mother to me most of the time. But still, I feel like it was my responsibility to do something for her, because I know she was expecting for me to at least to make her some dinner if not buy her anything because last night she told me that she put the carrots in a bowl in the laundry as there was no room in the refrigerator, just in case I needed any to cook something the following day. It's so cold in that room (which is not even used as a laundry any more anyway, but rather a storage room) so they can sit there perfectly happy without wilting one bit. She told me this, because I think she was expecting me to make dinner for her on Mother's Day.

Both my mother and step-father were out today, most of the day, not sure where as she doesn't tell me where she is going but last night she did tell me she would be out most of the day, after which she told me about the whereabouts of the carrots and the other vegetables.

Upon coming home, she didn't greet me and neither did I greet her (that is normal these days) and she was looking upset, but pretending that she wasn't while I told her that I removed more infected produce from the pantry (they were infected with pantry moth larvae or eggs) and resorted a few more items and told her that two of her food products on the bench were about to go out of date. She replied with some nonsense how "everything goes out of date some time" and I just walked away to my room. If she could actually be honest about her feelings, we could get somewhere, but she cant and so we wont and it will continue this way.

Earlier today, my guilt about not buying her anything was eating me up and I was thinking that maybe I should at least make her some dinner. But then I heard LayZ boy coming home with her car and that sealed it for me not to do anything. I felt even more resentful about her being so nice to him and treating him so differently to how she treated me, by showing him that he was her favourite, never doing anything about his obnoxious behaviour and never doing anything about the way he antagonises me on purpose ("he doesn't do it when I am around" or "I never see him do it"), so she enables him to be more vindictive and a shithead, by pretending he isn't doing anything purposely malicious to me. Instead of any consequences for his shitty actions, he just gets rewarded and no wonder he continues being a psychopathic idiot towards me, because he knows that his mother will protect him. It just hurt my feelings even more that she made sure he had her car, whereas she just yells at me, accuses me of stealing her keys (of course I didn't) and prevents me from even going into the garage by removing my keys from my handbag without telling (by furtively going into my room, rifling through my bad and taking the keys off the keyring). I wasn't going to show her any kindness either.

I'll just continue to keep to myself and stay disconnected from them, because as far as I am concerned, we don't have a relationship with each other. I just wish this guilt and feeling of responsibility would stop eating at me. I just feel guilty because I know she's upset and so I feel responsible for how she is feeling, as if, it's all my fault. I know it's not my fault, but all three keep telling me it's my fault, so it makes me feel like it is!