Chapter seven of The Great Gatsby by F. Scott Fitzgerald is one of the most significant chapters of the novel for many reasons, and Nick's feelings about Gatsby change often throughout.
First, this is the chapter when Gatsby stops holding his lavish parties, marking a dramatic change both in Gatsby's life and in his relationship with Daisy. The parties, we know, were designed to attract Daisy to his house; not only did they fail to do that but they were everything Daisy despised about West Egg and "new money." Of course the reason his house is now "dark" is that Daisy spends so much time there now, and Gatsby wants to protect her reputation.
This chapter is marked by excessive heat, symbolic of the "heat" that is happening in this story. One kind of heat is the sizzling relationship between Daisy and Gatsby; another is the slow simmer which begins burning in Tom when he realizes that his wife has been cheating on him with Gatsby. The heat is also evident in the Wilsons' home, as George has discovered his wife's unfaithfulness and Myrtle is desperate to escape from her husband before he moves away with her. Even even-tempered Nick gets upset with his "girlfriend" Jordan.
The dramatic confrontation in the hotel room is a critical turning point for everything that happens in the rest of the novel. Daisy does tell her husband that she loves Gatsby; however, Gatsby wants Daisy to say that she never loved Tom, and she is completely unable to do that. There is a great row, and at the end Tom is convinced that Gatsby's "presumptuous little flirtation" is now over. Everyone is experiencing the heat and the turmoil of what has happened, and Nick is relatively quiet about his feelings until after the tragic accident.
Then he says this:
I was feeling a little sick and I wanted to be alone.... I’d had enough of all of them for one day....
When he discovers Gatsby hiding behind some bushes on the Buchanans' property, Nick is understandably disgusted. As far as he knows at that moment, Gatsby cold-heartedly ran over a woman and did not even stop to help. His feelings toward Gatsby are evident here:
For all I knew he was going to rob the house in a moment; I wouldn’t have been surprised to see sinister faces, the faces of "Wolfsheim’s people," behind him in the dark shrubbery.
It is clear that in this moment Nick sees Gatsby as one of the thugs Gatsby has surrounded himself with and done business with in order to make all the money he hoped to lure Daisy with. Nick is sick of all of it--the money, the behavior, the connections, the lies, the carelessness.
As Gatsby continues talking about the accident, Nick's feelings do not change.
I disliked him so much by this time that I didn’t find it necessary to tell him he was wrong.
As soon as Nick learns the truth about who was driving the car, everything changes for him. Now he sees his friend as a rather pitiable figure. Gatsby is willing to take the blame for killing a woman because he loves Daisy, but Nick sees Daisy and Tom in the window and knows Gatsby has lost her.
Now Nick is concerned for Gatsby, telling him to go home and get some sleep, hoping his friend would be spared the sight of Daisy reunited with Tom.
Within the last page or two of the chapter, Nick goes from being fed up with all of these careless people to feeling sorry for Gatsby, a man whose dreams have been shattered but does not even realize it. Clearly Nick cares for Gatsby, and Nick's words and actions in the following chapters will show it.
He looks at him as if he's a liar and a very weak, sad person. This whole time, Gatsby has been pretending to be something that he's not, and Nick is extremely disappointed in the man he came to know.
At the end of Chapter 7, Nick sees Gatsby in a way we didn't before. It is this time where Gatsby tells Nick that Daisy was driving and killed Myrtle, but he would take the blame for it. In this chapter Nick knows that Gatsby has lost Daisy when he says, "There was unmistakable air of natural intimacy about the picture, and anybody would have said that they were conspiring together." This is when Nick starts to pity Gatsby for loving someone he could never have.