Depersonalization (or
depersonalisation) is an anomaly of self-awareness. It consists of a feeling of watching oneself act, while having no control over a situation.
[1] Subjects feel they have changed, and the world has become vague, dreamlike, less real, or lacking in significance. It can be a disturbing experience, since many feel that, indeed, they are living in a "dream". Chronic depersonalization refers to
depersonalization disorder, which is classified by the
DSM-IV as a
dissociative disorder. Though degrees of depersonalization and
derealization can happen to anyone who is subject to temporary anxiety/stress, chronic depersonalization is more related to individuals who have experienced a severe
trauma or prolonged stress/anxiety. Depersonalization-derealization is the single most important symptom in the spectrum of dissociative disorders, including
dissociative identity disorder and "dissociative disorder not otherwise specified" (DD-NOS). It is also a prominent symptom in some other non-dissociative disorders, such as
anxiety disorders,
clinical depression,
bipolar disorder,
schizophrenia,
[2] borderline personality disorder,
obsessive-compulsive disorder,
migraine and
sleep deprivation, and it can be a symptom of some types of neurological
seizure. It can be considered desirable, such as in the use of
recreational drugs.
In
social psychology, and in particular
self-categorization theory, the term
depersonalization has a different meaning and refers to "the stereotypical perception of the self as an example of some defining social category".
[3]
Individuals who experience depersonalization feel divorced from their own personal physicality by sensing their body sensations, feelings, emotions and behaviors as not belonging to the same person or identity.
[4] Often a person who has experienced depersonalization claims that things seem unreal or hazy. Also, a recognition of
self breaks down (hence the name). Depersonalization can result in very high
anxiety levels, which further increase these perceptions.
[5] Individuals with depersonalization often find it hard to remember anything they saw or experienced while in third person.
Depersonalization is a subjective experience of unreality in one's sense of self, while
derealization is unreality of the outside world. Although most authors currently regard depersonalization (self) and derealization (surroundings) as independent constructs, many do not want to separate derealization from depersonalization.
[6]
Just feels like I'm living a dream alot of times
It's more of a feeling of unfulfillment (that's probably not a word) 
