A cat's departure is silent, but the void they leave is loud

My heart is breaking and my pen is still. 
We had to euthanize Smudge today. 
There was no warning, no time to prepare. 
She’d been doing so incredibly well. 
She was fine Monday and Tuesday. 
Wednesday came and the decline was rapid and alarming. 
We woke up today, and she was yowling in pain and unable to stand. 
The veterinarian at first thought rat poisoning, but when we told him she had feline leukemia, he said that’s just how the disease is. 
They’ll be fine and then just crash and burn. 
My daughter and I stayed in the room until she went to sleep. 
That’s the least we could do for her, but we could not and would not stay for the final step. 
The last thing she heard and felt and smelled was love, was family. 
We gave her that. 
Even the sky wept this evening. 
We’ve not had rain in a long time, and the sky wept for our Smudge. 
Life is so unfair.