Upon arrival to your host country, you will begin to adjust to the food, time zone, climate, and language. This adjustment process can be overwhelming and frustrating, and you can experience culture shock. Although it may not seem like it at the time, this is a necessary step and is part of the adjustment process. Everyone that is abroad for an extended period of time goes through it and usually comes out smiling on the other end.
The following is an excerpt from Wikipedia:
The shock (of moving to a foreign country) often consists of distinct phases, though not everyone passes through these phases and not everyone is in the new culture long enough to pass through all three:
During this period the differences between the old and new culture are seen in a romantic light, wonderful and new. For example, in moving to a new country, an individual might love the new foods, the pace of the life, the people's habits, the buildings and so on. During the first few weeks most people are fascinated by the new culture. They associate with the nationals that speak their language and are polite to the foreigners. This period is full of observations and new discoveries. Like many honeymoons this stage eventually ends.
After some time (usually weeks), differences between the old and new culture become apparent and may create anxiety. One may long for food the way it is prepared in one's native country, may find the pace of life too fast or slow, may find the people's habits annoying, disgusting, and irritating etc. This phase is often marked by mood swings caused by minor issues or without apparent reason. This is where excitement turns to disappointment and more and more differences start to occur. Depression is not uncommon.
Again, after some time, one grows accustomed to the new culture and develops routines. One knows what to expect in most situations and the host country no longer feels all that new. One becomes concerned with basic living again, and things become more "normal." One starts to develop problem-solving skills for dealing with the culture, and begins to accept the culture ways with a positive attitude. The culture begins to make sense, and negative reactions and responses to the culture are reduced. Reaching this stage requires a constructive response to culture shock with effective means of adaption.
Also, Reverse Culture Shock (a.k.a. Re-entry Shock) may take place — returning to one's home culture after growing accustomed to a new one can produce the same effects as described above. The affected person often finds this more surprising and difficult to deal with than the original culture shock.
Culture shock is a state of dis-ease, just like a disease. It has many different effects, time spans, and degrees of severity. Many people are handicapped by its presence and don't recognize what is bothering them. Culture shock symptoms are really hard to seclude. There are no fixed symptoms ascribed to culture shock as each person is affected differently.