Need help to get over this feeling and go to sleep?

When a person I know dies I feel sad of course but then I get sick. As in my stomach hurting when my Grandfather's friend died, Or Steve Irwin's death I threw up twice and had a panic attack or right now since I heard that Ryan Dunn died every night (since Monday) my Throat tightens and it's hard to breathe. Why Do I feel like this whenever someone I was close to or a fan of dies or is killed it keeps me up all night.