Depersonalization (or depersonalisation) is an anomaly of the mechanism by which an individual has self-awareness. It is a feeling of watching oneself act, while having no control over a situation. Sufferers feel they have changed, and the world has become less real, vague, dreamlike, or lacking in significance. It can be a disturbing experience, since many feel that, indeed, they are living in a "dream".
~ Wikipedia
my sister and I call it "the double bubble". The feeling that you are inside a bubble, watching everything around you in a dreamlike slo-mo fashion.
They say that in these situations it is best to be around familiar faces and places, sometimes this physical closeness is reassuring.