Why does gene think everyone is suspicious?

Although Gene is of a jealous, competitive nature, he reveals in this chapter that he is not truly bad at heart; he cannot believe the bad aspects in his nature, and remains in denial about causing Finny's fall and about the fall itself. Gene becomes very guilty, and out of this guilt he becomes suspicious that maybe his classmates know the truth about the accident, and that he will be revealed for the wrong that he has done. He is amazed to learn that no one thinks that he played any negative part in what happened, but he also knows that Finny will be aware of what exactly happened up there on that limb.