Please stop worrying about this. Your life is way more important than to allow yourself to worry about this.
The Mayans were a very intelligent society, but they were not out to predict the end of the world. They had many different calendars for keeping track of many different occasions. The end of one calendar simply means what it is, it's the end. If the majority of the world didn't already adopt the present day calendar, the modern Mayans/ Mayans descendants would probably already have made up a new one. Furthermore, the ancient Mayans believed that those who witnessed the end of the calendar were incredibly lucky, and that it was a time of celebration.
Also conspiracy theorists are just trying to spread this around to make money. I've seen books and TV programs about this where all they do is try to scare people, and they are very good at it. Please don't allow yourself to worry about this. You will be fine.
Stuff You Should Know has a really interesting podcast about this. I think it will make you feel better. So please don't worry.
Is the world going to end in 2012? - Stuff You Should Know - CastRoller