This might be meaningless input, but there was one thing that came to my head that might be at least part of the problem. Do think that perhaps some of the reason nothing is working for you is perhaps because you are 'forcing' yourself (for want of a better word, I hope you understand what I really mean) to find pleasure? What I mean is, if I can figure out how to explain it... you are stressing/worrying that nothing is working for you, you are getting frustrated that nothing seems to work for you. So when you go to do whatever, you are hoping and aiming to get some stimulation and pleasure, and you are so focused on that aspect that you aren't relaxing and in turn- nothing happens. So then when you 'fail' and gaining any pleasure it adds more stress and makes it even harder the next time. Perhaps because that thought of 'will I or won't I?' is stuck on your mind when you go to do anything sexual it is affecting the outcome, or lack of.

You said you tried looking at porn- I know that I went and looked at porn right now and said to myself I was going to try and get off, it wouldn't happen, because I am trying to make myself do something I'm just not that interested in doing and frustrating myself when what I am trying to get to doesn't happen.

Perhaps something happened to you just before this all started and each time you fail it builds that feeling of not wanting to and not getting anywhere when you try. Maybe if you don't aim for anything in particular, just let things happen if they do but don't have a goal of getting anywhere in particular, then maybe some feelings will start to build again.

Then again I may have absolutely no idea what I'm talking about...