I’m tired of my mother calling me ungrateful and useless because I won’t babysit my sister whenever she wants.

For context, I’m 21F and live at home since I’m going to university for my bachelors. I get very good financial aid so family doesn’t pay anything. 3 years ago when I was 18 and about to move out of state for my first year, my mom had another baby. I was an only child my whole life and I was very unhappy when she told me she was pregnant because I felt like she wasn’t thinking of the implications another child would bring into an already very broken household. My relationship with her has been toxic since I was very little, and my dad argues with her constantly over every little thing. When she told him she was pregnant, he had literally no reaction, like he didn’t care.

I told my mom that if she was keeping it (which was guaranteed, we come from a very catholic household) I would not be taking care of it for her. I told her I would not change diapers, I would not wake up at night to help her, or stay back from social outings to help her when she needs a babysitter. After my baby sister was born, this is immediately what began to happen. I had to feed her, change her, put her to sleep, deal with her constant crying because she was velcro, and tell friends I was unable to hang out because I had to watch her.

Over 3 years, every single time I come home during a few day or month-long break, she is relieved that I’m home because that means I can help her with my sister. She often facetimes me on the phone not to check in but to have me calm my sister down when she’s having a tantrum. She tells me all the time when I’m gone how badly she wishes I were home because then I could deal with my sister when she behaves badly. This is because my sister respects me and listens to me when I parent her. For example, if my mother says to stop, she cries and whines no. If I walk out and look at her, she stops what she’s doing, looks guilty, cries a little, and stops.

We’re at a point now where if I say no to watching her or dealing with her I’m called a useless daughter who hates her sister and treats her like garbage. Mind you, I have never hit my sister. My mom hits her for crying. I offer her hugs when she has tantrums, and I have never not been able to calm her this way. If I say I don’t want to pick her up from daycare at 2, but at 3, I’m called useless because at 3 she can pick her up herself. If I say I’m too busy to give medicine to her (because for some reason, she refuses to take medicine when my mom gives it to her, but when I do, she is happy to take it), I am again called useless. I have watched my sister hundreds of times and practically mothered her. I genuinely don’t know what I can possibly do for my mom to understand that I’m not her personal babysitter, and that when I do help, it’s because I can and I want to. She has had constant support throughout this, with me and my dad and grandma all helping with my sister. Her constant insults are genuinely getting to me and everything I thought would happen if she went and popped a baby out when I’m fresh into adulthood happened.

Has anyone else dealt with this? How did you handle having a parent who expected you to help raise their child and then got angry whenever you tried to set boundaries?