Started a new job and now I can’t eat

Hello! I finally started working at the geriatric (I guess) age of 26, it’s only part time and it’s a super easy job but I am really struggling. Because it’s part time I work full time hours but only three days a week, which is working fine but it means I need tomorrow make meals I can take to my workplace. Only problem, I’m so exhausted from working I can’t get up the energy to make anything. Anyone have any tips?