You have my sympathy. I've been where you are and it's the toughest decisions I've had to make. I had one cat, which suddenly got sick and there was nothing they could do.) I had a dog that I had to put to sleep because of congestive hearth failure. It was tough but it was worse to watch labor of each breath. You are strong and doing the right thing. Take care of yourself afterward, it will not be easy, but go through one step at a time.