I don't think I actually fear death. I just don't want it to come earlier than it has to.
There are two main reasons for this:
First, chances are that things end with death, and then I wouldn't be able to do all the things I want to. Even if things do not end with death, I don't want to gamble about something I know absolutely nothing about.
Second, I have people that care about me. My death would probably make them sad, and I don't want the people close to me to be sad, and especially not because of something that I caused.

When I have reached my goals, done the things I always wanted to do, and lived a long and good life, I wouldn't mind getting my eternal rest. I might even think I deserved it.