The midfielder will lead his team out in their third and final group match against Russia in Israel this evening - he'll be too old for the U21s after that.
Germany are out of the championship after defeats against Holland and Spain.
"Sure we had hoped for more," Lewis told dfb.com. "Nevertheless, we can make only a compliment to the team in my opinion.
"For each of us this Championship was a great experience. We must now show in the last game against Russia that we were deservedly here."
Danny Rose played the full 90 minutes as England's tournament ended in a disappointing 1-0 defeat against hosts Israel in Jerusalem. Ofir Kriaf struck the only goal in the game in the 81st minute.
Steven Caulker and Adam Smith were unused substitutes.