My golden retriever (13 years old) needed surgery too, I felt like you, I can't do that to my baby even though I knew it was for the best, I snapped out of it pretty fast realizing I had to do the right thing to make him feel better. The surgery was scheduled for the next day, he was to stay over night that night, so after we knew everything was fine and he'd be coming home, I proceeded to drink a bottle of wine and eat a large pizza (the opposite of your problem). When he came home the next day and I could see his was feeling better, and better and better each day that passed, I felt much better and got my act together again. Don't ever think it sounds stupid because it's a dog, we have no children and our dogs are our life, we treat them better than some people treat their children I think, they are a part of your family and all they want is love and affection. So get your baby to the vet and have him fixed up, you'll both feel better - and just think if he's acting like he's 5, you guys can go for fast walks or jogs together to make you both feel great. Good luck and try to eat more, you're both worth it.