Rant about my mil

She wanted me to meet her at Walmart to get stuff for the baby. So I met her there she was late. She asked what I needed I said one of the soft blankets, thermometer, bath towels and soap, baby book. Not major stuff just the stuff we still need to get besides a carseat and things. Nothing she didn't get anything. I feel like she just wasted my time. Don't think I'm ungrateful because I'm not just frustrated because I wanted to come home little man is low so walking hurts and I'm super congested and she just aggravates me because she had me meet her special for no reason and all I wanted was to come home. I had already took my older 2 to school and my 2.5 yo was getting grumpy. Ugh