How to deal with the anger & questions?

My Nana is getting more and more angry and takes it out on us. We understand that she is frustrated at her memory loss and it’s annoying to her. It’s annoying to us. Especially when she asks the questions over and over and over… it’s hard not to get mad at her. We know she is not doing it on purpose and it is from the disease, but it’s hard when you are in the moment and she is asking the same questions for the 20th time.  We have been trying to rotate family members every few hours, but she likes some more than others and gets really mad when I leave for example. She doesn’t like my Mom as much as her caregiver or even as a guest in the house. I read about ‘redirecting’ them to something else to focus on, but it’s hard. How can I make my self not be mad? How can I really be a good care giver when she is driving me crazy? Any tips or suggestions to help us?