You may feel sadness, grief, a sense of anger, betrayal, and all of the other feelings that accompany a great loss. There are no right or wrong ways to grieve and the experience of grief is different for each individual. Talking about your feelings of loss with someone who values animals similarly, or with someone you trust can be helpful. If the person you talk with doesn't understand, find someone else. This is a great resource for support and information about the loss of a pet and the grieving process.
Many people use rituals to help with the grieving process.
When a companion animal has a health problem that seriously compromises his quality of life or has a significant behavior problem that cannot, after genuine effort, be overcome, euthanasia is often the most humane decision. For evaluation of health problems, rely on your veterinarian's advice, but please don't be afraid to seek a second opinion. You may need some time to decide what to do about your pet's remains. Lay a piece of plastic out first, then spread newspaper layers on top. You may lay your pet's body directly on top of the newspapers and cover her with a towel or a sheet.