I understand that no words can ever express the pain you are going through at this moment. Its never easy to overcome grieve, especially overcome the painful memories of a very very loved one. Sometimes, it is true that we loved our pets even more than yourself.
Life is indeed very impermanent.
All life on earth including we human beings and our beloved pets have to end our life one day. It is just the matter of the different routes we have to take in order to end the journey. What matters most important is the quality of life. Though the quantity of life is very important, it is still the quality of life that matters most. Coco is indeed very very fortunate to be borned into your family and really growth with your family all along these years.