Sorry you are having a bad week - sometimes its like that, and you do wonder why. Kids can be so cruel. I was bullied by a girl at primary school, don't know why she picked on me. But to this day, I still remember dreading playtime, knowing she would be there to push me around, and call me names. I finally told my dad, who insisted on going to the school. In those days, the cane was still used, and I think the headmistress threatened to use it.....cos this girl came and apologised, and offered to be my friend (not that I was keen, you understand!)
As to your cat, thats sad, but I am sure your cat enjoyed its life, crossing the road, and dicing with death - just unfortunate it did it once too often. But it was much better and happier doing that, than cooped up indoors. Children do cope with death better than us adults, who tend to dwell on things.
Do hope things look up for you from now on.