The expressions that you used ("deathly ill", no sleep tonight) make me think that you may be lacking some perspective and/or are identifying too closely with your body.
Sometimes, it pays to take a step back and contemplate on the fact that you will eventually die. If you vividly visualize that projected moment of your death and make it real in your mind, you will realize that possible problems you may be having in your everyday, mundane life now appear insignificant. You may also be filled with anxiety and dread. Alternatively, you may dissociate.
It is that dissociation that will allow you to identify with something other than your body (nothingness) and thus be free of such (unexamined) reactions.