So sorry to hear this. Dogs are very special. I have had to put down three in my lifetime, and although they were up in years it does not make it easier. Remember the little things they did that made you laugh, and know you gave him a good life and much love. When you can, adopt another. There are so many wonderful dogs that need homes. It will help fill the void in your life, and help a dog that needs a loving family. My thoughts are with you.