history: My sister's cat got sick and had to be put down last week. Feels bad. I'd known the cat for 14 years and was always her favourite person My sister's cat got sick and had to be put down last week. Feels bad. That sounds terrible. But hopefully it isnt suffering any more. 
current: She had stomach cancer, so she was in a lot of pain. Definitely the right thing to do
next: I agree, just remember her for all the good memories. 