Do you ever think that maybe the Mayans got sick and tired of writing down dates on a calendar? I pretty sure you wouldn't want to spend your whole damn life making a freaking calender. Or maybe they even died around the time they got to that point on the calender. Did you think of that?
Do you know how many times somebody said that the world was going to end, scared the entire world, though it didn't end up happening? The stupid "end of the world" predictions are complete and utter nonsense.
Nobody knows when the world is going to end, but I bet you anything we will all be dead before that ever happens. One day the world will end, of course. I presume it'll be when the sun expands to the point where the atmosphere gets totally eaten up that the earth won't be able to sustain life. That is just what I believe, but who knows, it could happen sooner.
There is absolutely know point in worrying, or even thinking about, when the world will end because we will NEVER know.