Sorry for your loss mate, like said above it's hard when they go (they are not just a pet, they are part of your family). I had to have my last dog a miniature Jack Russell put to rest as he had very bad epilepsy and the last fit went on for almost 5 hours. I still think back on him all the time and remember things like that when i would not play, he would take his ball and drop it down the stairs and chase it and go on for ages doing it.
My friends dog saved her life by nudging and licking her constantly after she passed out, dogs are real true friends we are honoured to shared our lives with.
The dog i have now is 10 and still fit and healthy but i've had to put her on senior food as she was having problems with normal dog food and i can't give her anymore human food which i hate as she watches you with one of those looks only a dog can.
Try and remember the good times and i'm sure your dog like most had it's own quirks, remember those and know that what you have done has saved your best friend from suffering.