I am so very sorry for your loss.
We had to do the same with our cat who was going on 18 years old.
It is going to take some time to grieve and everyone grieves differently, but I can promise you that with time .... you will begin to remember him with less and less pain and that pain will be replaced with a smile in your heart.
He is not gone .... he is just in a different place.
Hugs to you......
