I know there are probably a million PhD students feeling the same way - but I feel like I am on the edge of a nervous break down.  I am in the third year of my PhD, I have made zero progress in well over a year.  None of my experiments work.  I spend most of my time feeling depressed and phaffing on line.   I have never been to a conference.   Outside of the lab, I am not particularly depressed, I am successful socially and in sports and I leave my worries in the lab.
I am used to being quite successful at my work so this is really driving my insane.  I have been stuck in a rut for over a year now, I need something to start working, but I have gotten to a point where I just don't care anymore and I am just trying to hang in there and weather this whole experience out.  But that is not going to get me a paper for sure.  I need motivation, I need advice, any advice, please.   :(