Don't understand my grandma. I love her don't get me wrong I would do anything for her. But…

Don't understand my grandma. I love her don't get me wrong I would do anything for her. But sometimes I don't understand how someone can possible yell so much. I do a lot for her. I clean and cook and always make sure she has a clean house, and am always respectful. She is in a bad mood today because my uncle uses her non stop. (It's a long story but right now he's living with us) so she is taking her anger out on me and it's hurtful. I don't know what to do and it's really getting bad