No matter how hard I try to feel differently, I want to hurt myself. I think about suicide nonstop. It takes so much energy just to stay safe. Why?

Crisis Intervention. According to nimh, "if you're suicidal, you should be with other people and should not be left alone. Seek help immediately from 9-1-1, an emergency room, physician, or mental health professional. If it takes "so much energy just to stay safe" you might have a mental disorder that requires professional intervention and treatment. Please get with others immediately.