I felt the exact same way when I finished her route but I posted about it over on Fuwa (I quoted it below in spoiler)

>!The start to this route was very rage inducing to me as Kouhei proved to be an imbecile and being a pushover even after promising to protect Aeka. Once he started to actually fall in love with her is where it picked up, and then the plot twist with suicide and Aeka asking Nanjou to kill her. I thought he was honestly the biggest moron and wuss ever during it until he protect her. I share a similar experience stopping a bully but not a bully who does things to this extent. The humanity levels in these bullies were just sadistic. Relentless on Aeka, then on Kouhei. The fact that even teachers were part of this was an all too realistic depiction of how reporting bullying usually goes, or the fact that if you're targeted your "friends" will show their true colors. Now lets move onto the ending sequences. One phrase. WTF. All of that was such a plot twist, and really shows how quickly humanity can be destroyed in a person. I sincerely thought Kouhei was gonna get Nanjou to promise to not mess with them ever again. They got me with the sadistic twist, never thought they both would choke her at the end. Truth be told I felt a little queasy during the choking thing and was like "no way they're actually going to kill her" then came the "Lose control of bodily functions" right before death. Then it turned out she survived. That queasiness went away quickly! I understand why Kouhei started choking her, I mean if your gf was being sexually assaulted in front you, you'd definitely want to kill the person doing it and their accomplices (AKA Nanjou and her bf). But man, for an older title, this was especially gruesome, realistic, and beautifully written.(Also it came out near the same time as School Days so I mean)

Now I am afraid to go to the other routes because I know her situation and what is happening if you don't do her route. Makes you feel guilty.!<

At the time I was very emotional and still believe the route to be one of the best written I have ever read and it connected with me as I dated someone just like Aeka who was mentally messed up from all the shit that happened to her.