Well, look how long time we've survived already - billions of years. Why should a meteor kill us now, in our lifetime which is only a fraction of these billions of years? Now, when we for the first time in the history of the planet are the able to defend ourselves. Just think about how many amateur astronomers who are tracking all the possible threats, and all our missiles ready to destroy them. Some people say it won't help blasting meteors, because it will just turn them into pieces that will destroy us equally. I don't think that's true, since the smaller objects would burn up faster in the atmosphere, and we can possibly also change the direction the asteroid/comet would be traveling.
And at last, it is best not to think too much about fears, especially those you can't change. I know it's hard, and you probably try not to already. But think about the good things about the future, how our technology will advance, perhaps the singularity, robots removing the need for humans to work, perhaps you won't even need a job in 30 years, a full life of sparetime? There are so many exciting things about the future that could make me wish I was born in it, but most of us should be happy to be born in this already exciting time where our technology is advancing so fast, and we are gaining so much more knowledge every day. Every day we gain more knowledge to fight meteors and other disasters threatening us.