God Awful mate. I feel for you.
I refer to all of my dad's dogs as mine and it is terrible when they go.
This was the pick of the bunch, Oscar. In the picture you can see him favouring his right leg. It turned out to be bone cancer and he was 'put down' the day he was taken to the vet with little to no warning. I never knew a dog who craved human affection so much. He was 6.
I agree with the advice about getting a new dog after a bit but not another of the same breed as comparisons are inevitable. In a bit of gallows humour every time I get a phone call telling me the dogs gone. I say 'Can we get a puppy'. Mum thinks I'm heartless.