Sorry for your loss DB. I know how it feels. My best bud Nicky, an Australian Sheppard, passed away 2 years ago and not a day goes by that I don't think about some of the crazy stuff he used to do and it brings a smile to my face.
Very sorry for your loss. You can never replace the loss of a best friend or the memories you shared, but when your ready, you can change the life of another one who has a lot of love to give, but has never had a chance to have a best friend.
I think of em as chapter markers.
Another dog, another chapter.
They're always tough to lose, but there's hopefully always another chapter.
I had my kid mutt, my 20's single guy border collie mix, my #1 of all time border collie that helped me raise my kids and now I've got my grandfather black lab.
Different types, different roles, different chapters; all important.
Feeling what you are going through right now, as we went through it in April last year when we had to put our beloved mate down due to severe arthritis. Jessie was a 15 yo Border Collie.
It was one of the hardest things we have ever done!
We missed her then, and we miss her now even though we have a 6 months old BC puppy filling our lives with joy. You will never replace a much loved pet but in time you will have room in your heart for another.