Johnson is intent upon producing his best on a sustained basis for the Black Cats to win an international recall.
Johnson told Sky Sports News: "Playing for a winning team that's flying is so much better, and it's difficult when you are in a bit of a battle.
"My personal form could be better and we are going through a tough time as a club. All those factors have a bearing on the squad.
"It's difficult to watch from the outside. I have got to work hard and do my best to get back in that squad.
"I have been in a few squads with England with Roy Hodgson as manager. Hopefully I'm not being forgotten about. I have got to keep working on my game and when we pick up hopefully I will come back."