The hearts of men grow cold in the last days. Humanity, being of a sinful nature, has a default state of total depravity. Any sense of goodness in you actually comes from God pleading with you to do right. If you are losing your empathy, try to remind yourself of the state of the world and how everyone is potentially capable of good and evil. Hate the sin, not the sinner. Don’t let your heart be hardened. Keep it soft and fleshy.