AITAH for not wanting to do favors for my mom?

(25F) I currently live with my parents but I pay rent as does my sister (21F), my parents paid their house off so our monthly payment (1,000 each) really is just for food and other house expenses. Me and my sister work full time and get home pretty late so we like to go out on the weekends to have some fun. Lately my mom has been asking us to run errands for her every time we go out which is kind of annoying considering I want to use this time to enjoy myself. I suggested she ask my dad instead since he genuinely doesn’t do anything around the house and she got mad at me as she said i’m “already out anyways” and that I should be a better daughter to her. My problem is that she asks us favors every single time, and is never appreciative. Additionally she will ask us to buy stuff like groceries that should be covered with the money we already give her monthly. Whenever I buy something for myself her first question is always “why didn’t you get me one too?”. Although my sister is also tired of this she refuses to back me up because she enjoys their approval. I let my mom know it was not fair to us as my dad does not do anything and she never seems to be satisfied with what we do for her, she then told me that she did so much for me growing up and that she would never ask me for another favor again. Even going as far as giving me back a dress I bought her as a gift saying she didn’t need anything from me. AITAH?