According to the big bang theory, in the beginning there wasn't 'nothing'. The universe was squashed down into a high-energy, super-small (possibly point singularity) 'ball'. It's erranous to think of the big bang as an explosion; think of it more as a sudden, rapid expansion. And of course the soup of gases came after the big bang when it had expanded and cooled. Two main pieces of evidence for the big bang: we know that the universe is expanding (from the Doppler effect), and so logically we can assume that the further we go back in time the smaller the universe was. Also, the background radiation is constant, which supports the theory that the universe was originally very small, dense, and high energy.
(I'd also like to point out that the cleverest people in the world have come to accept this theory as the most probable explanation for the beginning of our universe.)
You're right that the first law of thermodynamics states that energy cannot be created or destroyed - it just changes from one form to another (and so is in effect eternal). Over the years many people have put forward that energy must therefore be 'God'. So, yes, of course energy is eternal. But in no way does this prove the existence of a supernatural being who answers prayers, heals the sick, and demands ancient Arabs sacrifice their infant sons.
We know Earth was 'created' about 4.5 billion years ago, when molten rock came together under gravity and then cooled. It was captured by the sun's gravity and began orbiting, just like billions of other planets around billions of other stars in the universe. And yes, it just happened to be in the right place to sustain life - but that isn't so hard to believe now, is it? We know that there are billions and billions of planets orbiting stars out there - is it really so hard to believe that one of those planets (ours) happened to be in the right position to sustain life? No, of course not.
And then the good old watch analogy. I'm surprised you didn't opt for the whirwind in the junkyard making a jumbo jet - I think that's a little more famous. Completely wrong, though. Evolution is an extremely gradual process of some mutations being beneficial, and therefore likely to pass on to future generations through genes. It is not a massive leap to 'voila, we have a new animal!' I recommend you actually read some books on evolution.
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