Two excellent writers I follow have been independently writing on the same subject: Kyle (A Deeper, Darker Ocean Green), in Psychopath, and Nixie (Musings from the Well), in an entire series (!) called Disturbing the Disturbed. Both would like you to know that you are not a psychologist, you don't actually know what the signs of mental illness are because everything you've heard about them is the second-hand grossly-oversimplified theme park version, and, basically, you just don't know enough facts yet for your self-diagnosis to be worth sixpence.
Go on, go and read. They are fascinating. Detailed. And right.
Don't fret, though. You're not less special because you're not crazy. In fact, you already have enough of your own psychological problems to get in the way of accurately understanding yourself and the world around you without having to claim psychological and emotional disorders as well!
So, next week, we get to talk about normal psychology and cognitive biases.