MIL problems... Big time

I'm getting to the point of snapping. Today this woman decides to get super upset about my WIC card and how yesterday was the last day. Yes i know it was! I only have 3 dollars on it left and wth can I buy with $3 on WIC? Unless I just get milk because that all I had left for me to buy on there. Plus if I were to buy the milk they wouldn't drink it because they're picky as hell! She literally left the house. The cheese was left out, there was plates in the sink, and the bread was out and opened. She was gone for 5 hours. Then she comes home and my SO asks her what's wrong and she blows up and says that I'm lazy and I do nothing and did nothing today when I cleaned the dishes wiped the sink the counters and swept the whole house. I also folded some of the clothes that she had out. I just don't understand. I try I try I try and she just doesn't care... Idk what I'm doing wrong for her to be like that. I work and the days I have off yes I relax but I help when I can. Idk... Maybe I'm lazy