“Re-entry into one's culture of origin is more stressful, with more unexpected consequences, than a transition into the unfamiliar,” they claim. This reverse culture shock (also known as re-entry shock) is all the more devastating because no one sees it coming: expats fully expect to be confused and frustrated in a novel cultural environment, but not in the home culture they know so well.

I'm not an expatriate, and I'm experiencing it.
Felt kinda lonely when no one came and fetched me (guess it might not be the sending off that matters, but the fetching pple back. must keep this in mind in the future). and then having no phone to contact anyone.
messages sent out with no replies made me feel forgotten, even though it's only been for 10 days.
feeling disconnected from people around.
dispensable.

"Young Yun Kim, in her book Becoming Intercultural: An Integrative Theory of Communication and Cross-Cultural Adaptation, writes that “a healthy psychological state is a dynamic fit between parts of the internal system and external realities – that is, an attainment of internal coherence and meaningful relationship to the outside world.”

It is the absence of this connection between the self and the new cultural environment that leads to what Kim calls “a serious disequilibrium within the stranger’s psyche.” It can manifest itself in the following symptoms:
Sadness
Loneliness
Homesickness
Idealizing the home culture
Stereotyping host culture nationals
Dissatisfaction with life in general
Loss of sense of humour
Sense of isolation, withdrawal from society
Overwhelming and irrational fears related to the host country
Irritability, resentment
Family conflict
Loss of identity
Feelings of inadequacy or insecurity
Negative self-image
Developing obsessions (health, cleanliness)
Cognitive fogginess, lack of concentration
Depression"

and i'm experiencing some of these as i'm in Singapore, back from Italy O_O