Depersonalization is the feeling of being disengaged and withdrawn from yourself and your surroundings. The world around you feels surreal. As if you are watching everything happen to you but have no control. While these feelings can emerge anytime, they generally happen to someone who has experienced trauma, such as the death of a loved one, and is having difficultly handling it.
Psychologists believe that this is a way the mind protects itself after the traumatic event. Depersonalization is not considered a disorder unless it becomes frequent enough to disrupt normal life and functioning.