I don't want to live anymore. But my family needs me.

I don't know what to do. I hate my life. I hate my job and my career. I feel like I don't have a place in the world. I feel worthless. I've always been alone. I'm 30. My health is not good. I have no social life. I have no friends. And I'm too old to change things. I don't know what I want but I know I don't want to live this way. But my family depends on me. I can't leave them. How am I supposed to go on living.