I wouldn't worry at all about the Mayan calendar. What has the Mayan calendar ever successfully predicted before it happened? Nothing, just like Nostradomus. On the other hand there are plenty of legitimate things to be worried about.
For example, the supervolcano below yellowstone is 30 million years past due for an explosion. The last time it blew, Nebraska was buried in 10 feet of ash.
Or you could worry about the magnetic poles of the earth reversing, which is overdue by about 250 million years. A temporary lapse in the magnetic fields of the earth could very well allow in all the cosmic radiation that is currently being blocked by said magnetic field, and fry everyone.
Or you might choose to worry about an asteroid. Think the government is actively searching for asteroids similar to the kind that have caused mass extinctions in the past? They aren't, which is probably a wise way to save money, since we don't currently have the technology to do anything about it anyway. An asteroid could hit at literaly any time, and we wouldn't have more than a few seconds warning between the time it hit the atmosphere and hit the earth.
If you want to think on a smaller scale, Iran (national motto: death to America) will soon have nuclear weapons. North Korea already has nuclear weapons and rockets capable of carrying these weapons as far as Seattle. Then there are Pakistan and India, two nuclear powers who have been on the verge of war several times within the last year.
But scared of some vague prophecies from a now defunct civilization interpretted by people with no understanding of the civilization or how the calendar actually worked? You have absolutely nothing to worry about there. Hope this makes you feel better.
