Feeling Not so good

I don't write about sad things in the blog , but this has to be so I can take it of my chest and move on .. well it involves death of a living things (its a cat) . well when stuff like this happens my feeling towards God's big plan for everything takes a bad turn . Makes me move from being agnostic to being atheist .Let me explain why, if GOD had a plan for everything in this world , and this is the way the plans to execute it well god is a sadist then . The cat was run over by somebody and it laid in its own blood for 3 days then was rushed to the vet where they said cant save it and had to be put down

people involved :

1)The person who ran over
2)The owner
3)The Vet

well lets us consider the events:

1)owner lets cat outside everyday and it comeback so it doesn't feel bad
2)the person who ran over didn't care to pick it up or even stop and do something so
3)The vet who had to put down the cat

well coming back to moving away from god consider GOD made everything he made the cat, he made the owner who loved this cat and cried for it when it was put down god made the person who didn't do anything after running over . made him to lie in pool of blood till the owner could find it and then told by the vet it cant be saved . if this gods plan for everything Iam out. Please GOD leave me out of your plan and scratch my name from your list (Thanks)