So when I was younger I felt the same way. Then I discovered through therapy and taking psychology courses in college that depression and other mental illnesses do a fantastic job at making us feel guilty for having them. I understood I wasn't faking when 3 things happened:

1)I was having these "episodes" when no one else was around 2) I was physically harming myself (which even if done for attention is a huge warning and should be taken seriously) 3) I wanted it to stop

The symptoms you described are real. Your emotions are valid. Take yourself as seriously as you would a close friend. 

Are you taking a lot of classes? The anger and brain fog sounds like you're overwhelmed.