Why is there something rather than nothing? By 'something' I include space and time themselves, not just things that exist within them.
I don't know.
Nobody ever will – any explanation would utilise logic and laws of physics, both of which are 'something' and so the explanation would be bootstrapping.
Positing 'god' doesn't get around the question – the posited god is a 'something', and raises far more questions than it answers.
So get over it – accept that there are unknowable things and don't be scared by it.