Not feeling compassion

I have noticed I don’t feel as much of compassion for others as I used to when I was more negative. I no longer watch the news and don’t dive into conversations about bad things easily. For example, when a tragedy happens and people die I say not much. I come off as a cold person. If I feel compassion, it hurts my body, I can’t let go off it for a while. So I choose to not really go into these bad events. I am becoming cold. I have been told that I am not compassionate and sometimes cold. How do you feel more compassion toward people without feeling physically ill?