Maybe you were abused or mistreated by authority figures when you were young. Maybe someone managed to penetrate your heart and do such chaotic and ruinous things that you cannot believe you have any value. If anybody really knew the real weakness and decay in there, they would never come near you or have anything to do with you. At times you can make the feelings go away and go on with life, but then the wall of water comes back, and there's no way out. Nobody ever wrote more profoundly about what it means to be beaten up inside, about tragic spiritual experience and soul sickness, than David, although he was a great king, and among the most gifted human beings, who ever lived.
Failure leads to rejection.
Marriages, friendships, and friends fail. People who once loved me have drifted away. It's feeling like a worthless, broken piece of pottery that is kicked aside and left in the dust. No one will ever care for me. I'm the kind of person who deserves to be alone and unloved.