It's so difficult when you're on a trajectory that you know will kill you yet you cannot change it because it feels like your entire being is so tainted and the sadness is so ingrained in your soul that your mind just tells you to isolate your miserable existence from those around you. I have struggled with this my entire adult life and I'm writing this with tears in my eyes because reading this beautiful piece is like unraveling my own future. Rest in peace, George. We all die alone, but no one deserves to die lonely.
I promise you, I felt the same way as you describe for years. I took antidepressants for years but they would eventually stop working. I tried all kinds of natural supplements, meditation, exercise, etc. After losing my marriage and alienating my children I tried once more but this time my doctor added a mood stabilizer. It has made all the difference in the world. I have a very close relationship with my children now, close friends, job, and enjoy many interests. Don't give up.