I’m having a hard time with death

The concept of dying and death is really getting to me. My loved ones dying slowly and in agony. The physical and mental pain they endure before they die, often years/months of agony. I do not understand this. I do not understand why God allowed this and created us to start dying when we are born and the hardship and excruciating pain faced before our end. I’m really having a hard time with this