I remember that feeling well from my first year of college in the States. I had been the best English student in my high-school class and I was in total shock when I came to Tennessee and couldn't say a whole lot. I was fine in class and I did my school-work well but I was very unprepared to interact with peers. Chinese history: no biggie. Planning a dorm-party on a Friday night: bring out the dictionary! 

Now I wish I hadn't been so hard on myself and I REALLY wish I had known that all of a sound it would be just fine. I am not sure how it happened, but one day I couldn't speak much English and the next day I could.