Mother not speaking to me. What would you do?

So my relationship with my mother has always been rocky. She was extremely strict on me, I was the only girl, and held double standards for my brothers. I moved out in January, I’m living with my fiancé. Even though I’ve moved out, I still help my mom with everything. If she needs something ordered, she’ll call me and I’ll do it. If she needs something explained to her, like her mail, she’ll call me. My fiancé and I buy and deliver groceries for her. I give her money, even when she demands it, and she has never paid me back even when she said she would but she always pays my brother back. She has my older bother still living at home but she’d rather call me to do everything for her. After I paid her credit card bill, she stopped talking to me. I haven’t spoken to her in 3 days. I called her multiple times yesterday and I texted her. She read my messages and didn’t respond. I texted my brother to see if she was ok and he said she was fine. I called her again before I went to bed and she had an obvious attitude. I kept asking her what was wrong and she wouldn’t say. At one point she was just silent and then she hung up on me. My fiancé thinks it’s because we didn’t take her to the grocery store this week but we’re human, we forget. This definitely sounds like her. She’s extremely childish. Another reason I think she’s mad is because I didn’t get her anything for Mothers Day. Every year she expects something for Mother’s Day AND Dominican Mothers day (on the 29th). I have given her gifts for both days in the past but that is not something that I could do right now. I had decided to get her something on the 29th. We did call her, my fiancé and I, to wish her a good Mother’s Day but maybe she didn’t think it was enough? But also, she had me at 33 and sometimes I secretly get mad at her because it’s like DO BETTER, BE A BETTER MOM!! She was a grown ass woman and I was her last child which means she had other chances to get it right and she didn’t. I just get so angry sometimes, but I don’t let her see that. Anytime she needs me, I help BUT I have my own life! I reached out to her today and got no response. What would you do at this point because I’m lost. Do I keep trying to reach out to her?