Existential therapy is all about dealing with this kind of fear. Fear of dying, fear of living, fear of being forgotten. I doubt that there is a short or simple answer, but you can know that you are not alone since so many people have the same fear that there is an entire branch of theory and philosophy that deals with it.

Solutions could include finding the root of the problem (what happened when you were ten that triggered your fear of dying?) and attempting to resolve it, or finding a spiritual or religious answer that helps you to accept it, or finding a way to make your life more meaningful, and many more too.

Some information on Existential therapy:
http://home.earthlink.net/~andyda/ps.../keyexist.html