I don’t know how to help my mom

Hello everyone, I’m not english so I already apologise for future mistake. I’m having problems dealing with my mom, we are going through a rough time with money (like many people), but I believe she really overthink the situation and she’s making me very nervous. We have everything that we need, she just bought a new house for my grandma and we had zero problems buying things for Christmas or shopping, etc. But everytime we do something she starts talking about money and it really affects me. When I try to talk about this she gets angry and usually we end up fighting. I really want to put an end at this but I don’t know how and what to do, I’d like her to understand that in the world there are bigger problems and that she should appreciate what she has a little bit more, but she won’t listen to me. Anyone knows how to help me?