Why and how did i become apathetic about the negative aspects of my life?

Not apathy: Seek meaning instead. People who have survived horrorific childhoods may say, "i learned never to be cruel" / "i learned to appreciate the simple good things." I have many regrets but can say, "i finally learned how not to be a jerk" & made amends where i could. No life is perfect. Difficult relationships can be ended; you can learn a new marketable skill even if you have some disability.