Reverse Culture Shock
Culture shock is most noticeable when you leave your home to go to another country, but it can also occure "in reverse" once you have returned to the U.S. It's natural to miss your new international home. You might even find yourself negatively stereotyping Americans! These feelings and thoughts are to be expected, and something you will work through.
In the meantime, allow yourself time to readjust to your U.S. life. Seek support networks by meeting with students with similar interests and befriending international students. Ideal resources for you are listed here.