AITA? My mother in law just got super pissy because we didn’t tell her we were going to the grocery store.

For a little context I am 6 mo post op gastric bypass. I’ve recently hit a stall in my weight loss and started meal prepping again for my husband and I. We told her earlier that we were going to go out and run errands. She had plans to go to the grocery store to buy stuff for dinner any way. So when we got back from all of our errands-which was not only to go to the store, because my husband and I decided to go last minute to the store to save time; she said “well if I would have known you were going to the store I could’ve just had y’all buy stuff for dinner”. So now she’s acting like a child; stomping around and having a bad attitude. I also want to add that she only buys brand name things, and currently my husband and I have all the money we have for a down payment on a house. No way I was gonna buy all name brand things for one dinner.

So, am I the asshole?