The author Neil Gaiman did the same thing. But he was successful at catching the dog, which became Cabal, and changed his life.

And because this is the internet, I'll one-up your story...

It turns out that in a war zone, when the bombs start blowing up everywhere, and gunfire is going off, and your owners are completely out of their minds with stress and panic, you, the dog, find a way to get out of the house and run away from the chaos and noise.

And then your family leaves their home because the Serbian army is rolling into town and flattening everything and blowing everything up, so when you, the dog, eventually emerge from the forest a few weeks later when the noise dies down...

...everything you knew is gone.

So you find some other dogs, and join up into a group, and go look for food.

And you lose your sense of vehicles, and roads, and traffic, because, well, it's a war zone, and everything is crazy.

And then this guy comes bombing down the road at night in a truck, and there's blinding lights in the dark, and you freeze, and ... BAM! the truck hits you, you go flying off the road, and you die painfully and alone.

(I hit so many wild/feral dogs in the Balkans, I lost count. There was nothing you could do. You would be driving along, and suddenly a white flash and BAM and ... I just killed another dog. It still tortures me to this very day, how many dogs I hit just driving normally in the Balkans after the wars there...)