Yes.
I had to put my cat down last month. Heart failure. He was 18, and kept me alive for as long as he was old. I'm convinced he was a psychic alien cat.
He always laid with me when I was sick. If anyone got near me, he would hiss at them and stand as if he was protecting me. Every time I had pneumonia, he only left my bed to eat & go to the bathroom.
When he was dying, the last two weeks, my chest felt so heavy. I ended up in the ER because the chest pain was so bad that I thought I was actually having a heart attack.
When I put him down, the pain stopped. As it did with the tooth pain that I had, that stopped when one of his teeth was removed.
I miss him. I have a new cat, but you know, it's not the same. He's still adorable, though.