Greetings,
i have read through a lot of the posts concerning ed found on this board and the vast majority of them concern treatments for a possible physical problem down there. I am about as sure as I can be however that my problem is entirely in my head and I don't really know how to fix it.

It started when I was 17 and has gotten worse since then (i am 23 now). The problem started with me getting worried about losing my erection because it happened once during sex and has since snow balled. Now at 23 I am having incredibly difficulty maintaining it during sex (even though I can manage to get a very strong one for a bit). I get into a mental cycle where I worry about it and then try to stop myself from worrying, etc. And that causes it to go down and I am almost never able to get it back up in that session.

The problem is worst during sex but is starting to creep into when I masturbate too...It gets to the point sometimes where I feel almost a tightness in my chest from the stress.

I know people would suggest not thinking about it but I have tried and that doesn't work. How do I break this mental cycle? How do I learn to be able to think during sex and not lose my erection? This is driving me and my partner crazy and I don't know what to do, please help.