J41 comes to the rescue, having (re)posted these links recently on motivation. (Click
here and
here for them.)
Now, back to the issue. Anger doesn't usually resolve issues; people tend to rest on their laurels as soon as they achieve their supposed goal. I believe this might have been what has happened to you. I think the difference you need to make is not necessarily focusing on what others are doing, but beating your own personal best. Got a Rank 1, but a 93%? Try to get 94% (or more) and refrain from mistakes next time. Got a perfect score? Try to get that again. Doing this puts the competition upon yourself to do better (or repeat it) and won't be as easy. It'll be a constant competition against yourself. Who better to beat past you than present you? The best thing about personal bests is that it doesn't matter the mark you got beforehand; you just want to beat your previous 'best'. This will work whether you're the best or the worst in the class and won't be influenced by external forces (your classmates).
Hope that helps.