You may not have depression (as a disease) at all. You may have destroyed emotional, sexual and social life. And that is really, serious reason to feel bad, man.
I have a question for you. What is that you value most in life?
If your answer is porn, than even thinking about losing it will cause serious pain. Losing it for real - even worse. This is corelated both with neurobiological base of addiction, and your emotional nature as a human being.
What you value the most become the thing that influence all other things in your life. It's like the top of the pyramid. You construct all the lower levels of your life to support the top. If the top is pathological - all of your lesser values, and personal virtues are becoming non-existent, or corrupt as well. For what I know, and experience - the best solution to this, is to put at the top something eternal, uncorruptable, nonmaterial and ideal - like God. Only then you can structure all your major and minor life goals on the path to this ideal. It doesn't matter that you will never achieve it. It doesn't matter how, and what you call it. What you act is far more important than how you describe your actions. Action is primary to all description, and this is the real thing that shape your life.
Good way to discipline yourself is to make some goals (even small ones), breake them into smaller routine actions, and do the whole thing in baby steps without forcing yourself beyond your current psychophysiologicall capability.
I'm talking about life goals beside quitting porn in a way that other goal can distract you from addiction. Make a plan and start small.
If you have trouble with social interactions, than you can for example repost to someone else's thread here on forum once a day. Even if you do it badly without any social skill whatsoever. After that you can reward yourself in some manner (snack, 30min of videogame, buy small gift to yourself) - that will reinforce good habbit.
If you are interested in art in general, than I strongly reccomend Joseph Campbell "The Hero with a Thousand Faces". This is basically C.G.Jung written in an easy manner. Or if you are interested particular in poetry - the book called "Iron John: A book about Men" by Robert Bly.