In reply to psaunders:
I've been given rough advice (for running, not cycling) in an attempt to defeat the plague that I've reached (not a very high one).
I've been told to scrap anything fast from my schedule for at least the next six weeks. All training is to be conducted at level 1 and level 2 - conversational pace, or just a touch faster. The aim is to gradually build the long run and the time spent running over the six weeks and then introduce harder stuff slowly after that.
How this translates to cycling, I'm not certain, but as it's the same system that is likely to be stressed, this approach may be worth reading up on.
My overtraining has not been severe, mainly consisting of pushing too hard on most runs, but two weeks in I feel pretty good. Time will see if it works!