this bit makes sense, John thought maybe, MAYBE, Sherlock was on the mend; that he was on his way to being a normal human being. But now he can see the cold hearted thought process and he sees now how Sherlock has regressed. ---> THE FEEEEEELS
"I did everything I could to impress you."< Guys, he's been trying to impress John since day one when he realised how much he liked it. "Do you know you're doing that outloud? Never thought about this.