My Smudgey?

How do you find the strength to let go of your companion. My friend, my lady puss. I am sat here in the kitchen strokeing her, shes purring, but has this stomache tumor, she lies on the floor "cold seeking" which makes me think shes in pain. she eats like she is starveing, shes getting no nurishment its to feed the tumor i'm sure. It sounds like hyperthiroidism but blood test said nothing.At the moment I feel shes so sad, shes existing just to feed her hunger. My children want her to go on alittle longer, but I really dont want her to suffer. I have seen my mum die of pancreatic cancer so I know, i dont want her to suffer. I realise I have to be strong for her sake and ease her suffering and cross rainbow heaven, but when I come to think about putting her to sleep, I cant visualize the journey, its so final our friend who has entertained and amused us, been with our children growing up. We have cherished her our smudge. Get insurance for your puss wont after 8yrs-11 start now!!