Poor Tonka and poor you - sounds like the irresistible force meeting the immovable object, with a huge amount of pain and frustration and guilt and all made worse by nicotine withdrawal. But you and Tonka have been friends for so many years, and the human half of the partnership has to be the one to say sorry and find a way out of the impasse. It usually means backing up a bit, I've found, and making space for the other party to have their say. No doubt Tonka is stiff and sore, with diminishing eyesight and hearing, all of which make cuddles etc worrisome. And I rather agree with those who say feed him what he wants as long as it is affordable - the benefits of a healthier food are pretty marginal at his age. But I wish I was close enough to pour you a stiff whisky, stay for a conversation long enough to leave you laughing, and take Tonka for a few days to give you a breather. Are you sleeping enough? And don't ignore the suggestion of antidepressants - a short course can strengthen that wobbly bridge across the dark places.