Was there another universe before the Big Bang?

* before you start reading this I want you to know that these are purely my thoughts and I may or may not be right at some points because I haven't researched much *

So, we all know that the universe we are a part of, begun at The Big Bang, we have read about it everywhere, but what interests me now, is that what was there before The Big Bang happened? What was before the singularity? Well, to understand what I think about it, we'll have to make an assumption, that the Universe is NOT infinite, and there is, an end, of the Universe and it is in a sphere, not that hard to assume, is it?

Now we all know that the universe is expanding, Edwin Hubble discovered that, right? So IF there is a limit to the Universe, considering it is not infinite, this expansion has to stop someday? I mean, there will come a limit of the imaginary 'boundary' if the universe is not infinite. What if all the celestial objects, galaxies and everything, get to the end of the universe? It would explode! Just like you start filling water in a balloon, it keeps on expanding and then it bursts. 

WHAT IF, our universe, was formed in the same way!? What if what we call 'singularity' before the Big Bang was just another universe which was infinitely smaller when compared with ours and when it reached its limit of expansion, it exploded and that, is what we call The Big Bang? 

Now I know that the 'singularity' had infinite density and was infinitely hot, but can't that be for the reason that we are seeing it as a single element instead of a universe trapped inside it? The same way when we look at a cup of coffee and call it a cup of coffee instead of a "mixture of milk, water, sugar and coffee powder", and perhaps the reason we call it a 'singularity' is because when we compare it to our universe, it is infinitely small; even in life if we compare a hot air balloon with an egg, we might say that the egg is nothing when compared with the huge hot air balloon.

Basically what I mean to say is, that is it not possible that "our" universe, was born out of another, infinitely smaller universe which had reached it's limit of expanding and which exploded, named The Big Bang and formed our universe which is continuously expanding, and when we reach our limit of expansion, won't it be called a 'singularity' as well? Because all of this would be packed inside one, single element, which, perhaps would explode and form another universe which would be infinitely larger than our universe and when compared, ours would look nothing to the other... 

~ Guni

(image source - Google Images)