Gloom and doomers
There's been Gloom and Doomers crying about the end of the world as long as there has been spoken words. Global Warming, the impending Ice Age (funny how those two are holding the temps in near balance -- see Scientific American magazine last month, in your local library), running out of Oil, hole in the Ozone, over population (that's funny, check the average age in Japan and most of Western Europe), the aging of America, ebola, bird flu, the next pandemic whatever flu.
After you see a few of these come and go, you may develop a better appreciation for the resilency of humankind. Yes, individuals will die in volcanic explosions, viral epidemics, tidal waves, freak storms of all sorts. Some islands will submerge beneath the waves and others will be raised up revealing lost temples (see the coast of Laos after the tsunamie).
But, the end, the actual end, is not likely. There are always Doom and Gloomers ready to write a best-seller book on how it will happen any minute and how you need to follow them to save yourself. They typically end up very rich, but for those that convince their followers to head for the jungles and drink poisoned Kool-Aid (see Jim Jones in Guyana (?) in the late 70's).
So, chill out. Live each day as it it matters. Not as if it is your last day on earth, but just as though it matters. You are afterall an individual, and we all die one by one.