Why I believe in Multiverse, but not in Universe?

Om Namo Narayana. Om Namo Kesava. Om Namo Brahma.

I am a religious guy with interest in Science. I see Religion via Science and vice-versa.

Some Science journals claim Universe was originated from Big Bang and Universe is expanding. Now my questions are:
What was there before Big Bang? Can anybody define Time at Big Bang and prior to that? Doesn't it make you feel Time is an illusion or relatively variable? What is Space? How was Space created and where did Space originate from? Can our scientists define 'Space'? If Universe is expanding, then into where is it expanding? What is next after and beyond Universe?

Now, if you are intrigued by the above discussion, then read https://en.m.wikipedia.org/wiki/Multiverse_(religion). Kindly accept my apologies, if I sounded foolish. Feel free to correct me, if I am wrong. My love for Almighty made me write this post. I dedicate this post to Almighty who knows everything and guides me.