Returning to the United States can be a mixture of pleasure and pain: pleasure because you are returning to all you love in the States, and pain at leaving all you have grown to love in your host country. Unfortunately, leaving a new home, new friends, and a new culture you have grown accustomed to makes returning to the States quite a bit more complicated than just stepping off the plane.
This basically consists of feeling out of place in your own country, or experiencing a sense of disorientation. While everything is familiar, you feel different. Even walking through the airport and hearing American English spoken can be a very surreal experience. You may consider looking at the University of the Pacific's online course on culture shock, which also discusses reverse culture shock, and how to deal with it, very well. What's Up With Culture? 
People you were close with when you left, even those you kept in good contact with, will be separated from you by the unique experiences you have had in each other’s absence. However, this separation is certainly not permanent, and new experiences can make for some very interesting conversation. Just keep in mind that since both of you have changed, you won’t necessarily interact in the same way.
Since only you have had your experience, there is no possible way that anyone can fully understand what you have gone through. While people will be interested in what you did abroad, nobody will be quite as interested as you — despite your amazing storytelling skills.
Fitting your new life into your old one can be frustrating. Since every country has a unique approach to life, it can be difficult if you’re used to operating within cultural mode, or have made that approach to life a part of you, to return to the U.S. where the rules are different. It’s easy to become frustrated with aspects of U.S. culture that no longer make sense to you. Try to keep things in perspective. Bear in mind that every country has its flaws and its strengths. Also be prepared to return to all those little trials you left behind you. You might have journeyed far, far away, but they haven’t.
Returning home is wonderful in so many ways. You can talk to family and friends without a phenomenal fee, you can eat at your favorite restaurant, sleep in your own bed, and whatever else you were looking forward to doing. However, there is always the danger of falling victim to the “grass is greener syndrome.”
Just as it is possible to dramatize the glory of your return home, it is also possible once you’ve returned home to over-romanticize your experience abroad. Life is never cookie cutter perfect. Home is not the impenetrable haven you might remember it as at times, and life would still not be flawless, even if you were back in the host country you left behind.
A few things might make re-entry a little easier: talk to others who have studied abroad, keep in touch with those you met abroad, use the emotional momentum to continue cultural interactions (check out on-campus groups like Friends of International Students and Scholars), and be patient with yourself and others. Savor the rare privilege of having two ‘homes’!