Dear Teffiemoore,
your love to your dog will tell you very clearly the answer you are looking for.
Comfort your little friend and enjoy the remaining time to fullest. I found myself after Gino was gone looking at videos with him (I have only few and I am so really mad at myself for that!) SO, maybe you can take photos, videos and have a bit of a fun with your pooch while doing that
All I can tell you is that you will clearly feel and make the decision for both of you once the day comes. I wish you all the best and as many shiny days as possible to enjoy.
Peter