Hi Laura
One thing its worth thinking about is that far over 99% of matter is empty space anyway. In fact the big question is maybe "what is matter ?". So although the idea of just the earth inside a small point like this -> '.' is weird enough, let along all the stars and even all the galaxies in the same point, its worth remembering that matter itself is something we experience as "full" and "solid" is really an illusion of a combination of things such as our senses and the various forces in particles.
And this initial point is not like a small really heavy stone that contains everything in the universe. It IS everything in the universe at that stage. Not only is it all empty space - it is also time itself. So time from our is something seperate from space. Well actually its not - but in our normal lives it seems to be 3 different space dimensions and one time dimension - but at the moment of the big bang it was all a 'promordial soup' with nothing to seperate space from time.
In terms of what was before the universe, or what is outside of the universe ,that is something completely unknown. There are vague theories such as those from string theory that say two branes (one dimensional 'surfaces') collided. But the very idea of a collision outside of space is so theoretical that most physicists admit its almost meaningless speculation at present. Even though I rekon the universe was created by and contained within god, you should realise that in terms of basic physics there is no need for there to be anything outside of the universe. The smaller the scales physicists look into everthing is like a fizzy jungle of energetic things. Some propose one of these types of things could have popped from no where and then collapsed on itself and released enough energy to produce the universe. Like all this things, and like the branes, and for that matter like god, it always just pushes the question back further to "where did that come from then". Of course we think within a causal world and so we expect everything to be causal. But if time was created and is not an absolute thing - and actually the fact that time is not absolute was proven by einstein, then in many ways it seems there is an absolute kind of basis to reality in which there is no time. And maybe "All the worlds a stage..." and all that kind of thing...
Simon