The economy is not doing well. Unemployment is high, homes are worth what they were in 2003, and growth is weak.
But one sector is doing great: exports. They've been growing about four times as fast as the overall economy since the beginning of 2010.
This is part of a longer-term trend. Despite the myth that the U.S. doesn't make anything anymore, U.S. exports have actually been contributing a larger and larger share of the U.S. economy since the 1970s.