… shouldn’t you be keeping it quiet? God isn’t advertising. What makes you think He wants you to?
Saying the world is going to end is to say that everything will stop existing. If anything physical is left, the world hasn’t ended. After a natural disaster, people sometimes speak of the end of the world, and maybe it’s the end of the world as they know it, but the world goes on. It has just changed for them. Similarly, if the “end of the world” is a war or cataclysm of some kind, that’s not really the end of the world, just a change in the world that makes it difficult for humans to survive.
Have you noticed how the world ends and begins again in each moment? If the world ever really ends, once it has ended, you and I won’t be around to be happy or sad about it. If we’re still around, our world hasn’t ended.