Loneliness

Loneliness is an unpleasant emotional response to perceived or actual isolation. Loneliness has been described as social pain, a psychological mechanism that motivates individuals to seek social connections. This condition is frequently associated to a perceived lack of emotional connection and intimacy. Loneliness overlaps and yet is distinct from solitude. Solitude is simply the state of being apart from others; however, not all individuals who experience solitude feels lonely. Loneliness, as a subjective emotion, can be experienced even in the presence of others. Read more on Wikipedia