Losing my cat was harder than losing my parents. I sobbed for days when my orange tabby left for Rainbow Bridge. Some animal companions are what I call soul mates. There's something special about them and I think each of us have at least one in our lifetime. Your baby was your soul mate and he left a big doggie shaped hole in your heart.
I have a dear husband and when he's gone, I'll only have my cat family. And yes, they ARE my family. I was never able to have children like so many here but I have two stepdaughters who wouldn't notice if I was dying in the middle of the road. My cats are always there for me.
And FWIW, kitties make wonderful little listeners. They will happily listen to you and comfort you as you grieve.