It’s easy to forget that a life companion eventually succumbs to biology’s final act. Pets are there for us like a relative or spouse. A pet’s death can result in the same emotional repercussions that we think is reserved for our human companions. Feelings of sadness, isolation, anxiety, and depression are normal. Loss of sleep and mood swings are common with the loss of a cherished pet. Grieving is a process that take time and patience. Talk to people about your feelings. Seek support. Start by exploring these sites:
http://www.aspca.org/pet-care/pet-loss/
http://www.humanesociety.org/animals/resources/tips/coping_with_pet_death.html.