Feeling sad always

I have this habit of feeling sad. When I hear good things happening on others life I feel sad that it doesn’t happen in my mine. When I hear bad things happening in others life I get scared and feel sad about what if it happens in my life. I have this weird state of feeling sad no matter what. I’m not saying I should feel happy or sad but why is my default feeling tending to be sad.Im clueless here on how to go about changing this state. Any help to move forward and change my thinking here