Woah, my condolences.
I remember I had a little, 3 months old dog. He could just stay 3 weeks with us, but on that time i was really close to him. The first week was fine, this until on the second week we saw that he didnt do what he normally does, and also vomiting sometimes, so we brought him to the Vet, and he stayed out on there like 1 week, altought never going out. I remember going out of school, before going to the car, my mother got a call and after the call she told us sadly: Guys, Rocco (Rocco was his name) isnt anymore. I was 6 days wrecked and crying, so i guess I know how it feels, man.