Grief

"Grief is a multifaceted response to loss, particularly to the loss of someone or something to which a bond was formed.

Although conventionally focused on the emotional response to loss, it also has physical, cognitive, behavioral, social, spiritual, and philosophical dimensions. While the terms are often used interchangeably, bereavement refers to the state of loss, and grief is the reaction to loss.

Grief is a natural response to loss.

...The grief associated with death is familiar to most people...

Loss can be categorized as either physical or abstract, the physical loss being related to something that the individual can touch or measure, such as losing a spouse through death, while other types of loss are abstract, and relate to aspects of a person’s social interactions."

http://en.wikipedia.org/wiki/Grief