Complicated grief is unresolved, incomplete or unfinished grief. It usually is characterized by a prolonged sense of mourning and often occurs in conjunction with underlying psychological/psychiatric issues. Clients often describe themselves as “feeling stuck” in their grief. Complicated grief is not intrinsically pathologic. You are not crazy just because you are having a hard time coping with loss!
Complicated grief occurs quite frequently in pet loss and can contribute to behavior changes, depression, anxiety, obsessive-compulsive disorder, post-traumatic stress and compassion fatigue. Symptoms of complicated grief may include: continued disbelief in death of the loved one; inability to accept the death; persistent flashbacks, nightmares and intrusive memories; and continuous yearning and searching for the deceased.
Anticipatory grief is the “normal mourning that occurs when a patient or family is expecting a death…it includes all of the thinking, feeling, cultural and social reactions to an expected death that are felt. . . . [I]t includes depression, fear, anger, sadness, extreme care for the dying person [pet], time/action in preparation for the death and time to complete unfinished business” (from http//:www.cancer.gov). It is likely we will outlive our pets, so one could say we are anticipating their deaths from the moment we acquire them.
Disenfranchised grief is experienced by an individual after a loss that is not socially acknowledged or supported. The loss does not “fit” into societal rules for mourning. The mourner is often left to cope with his/her emotions related to the loss with minimal social recognition of the loss or support. Mourners are expected to continue with normal routines (e.g., coming to work, not having or attending memorial service/rituals). Pet owners often experience disenfranchised grief when we hear statements like:

“It’s just a dog.”
“You can get another cat!”
“Are you really that upset about an animal?”
“Oh well, there are so many other animals who need homes!”