I'm gonna do it and I don't think I'll change my mind

I've been feeling really down for several months now, having moments of false hope when it seems like things might get better, only for something to happen that brings me down again. Today I realized that it makes no sense for me to live a life where I'm constantly suffering. I don't want to talk too much about my personal life but in the past I've hurt myself, whipping my back with my belt or making shallow cuts on my hands with a knife. Even though I stopped self-harming a long time ago, I still feel really bad. I've already tried not to isolate myself and talk to those close to me but it hasn't worked. I live alone and I wrote a letter that I left on the table. As I was writing it, I hoped I'd change my mind but instead I've become more convinced to do it. I don't have the courage to take a knife to slit my wrists or my throat, at the moment I'm starving and avoiding to drink. I know that my loved ones will be devastated if they find out about my death but I'm doing this more as an act of love towards myself and out of simple selfishness