I hate my MIL

How could one woman be so stupid who had children herself?!! She comes to visit and gives my 22 month old a drink out of her water bottle container. She did this even though he had his own water cup in front of him and as I was coming back from the living room to grab my water bottle which he likes. She knew damn well what she was doing. I’m 34 weeks pregnant and now I have to go get covid tested because my son and I share my water bottle, of course he is my child! I know we don’t go anywhere or put ourselves at risk. I’m furious that I allowed her to come visit. I f***ing hate her!!! She’s careless and irresponsible and I don’t want her in my home ever again!! 🤬😡