I don't know what to say I screwed up at work, I've been working long hours 12 hour shifts they are only paying me for 8 hours

And I missed something. I hate my job so much, I can't afford to quit and I feel trapped. I've been crying all morning. I haven't been able to find anything that pays a livable wage here and I've been trying but it's hard when you are working so many hours. I can't afford to live if I quit and I don't know what else to do this job is killing me emotionally and physically. Bar none the worst job I've ever had