Warning: Angst Ahead.

Now with that in mind let's take a look at the word "apathetic" :

A: From Greek a-. A negative prefix meaning "not" or "without". E.g. atom, "Not cuttable"; amoral, "without morals".

Pathetic: You know this word. See where I am going?

But really, I'm just not having any fun anymore. I'm not happy. I'm not inspired. I'm not excited about anything. I'm not even angry about anything. There is nothing I want see. Nothing I want to do. I am completely without purpose, entirely ineffectual, absolutely insipid.

There is nothing about my life that is particularly pitiable. If I had an ordinarily happy life I would be content to be just happy. But what I have ended up with is an ordinarily miserable life. I'm not so interesting as to be pathetic, thus (intentionally twisting the word) I am apathetic.