I've been reading up on Poliquin's stuff like crazy and just yesterday actually experienced overtraining again for the first time in about 5 years. I haven't taken a week off in the last 4 months, and I started experiencing insomnia/depression. Noticed that my body weight had gone down from 220 to about 211-212 in a day. He wasn't joking about that.
After re-reading the 5 elements article, I realized that I definitely fall into the wood type category: have to really reel in volume and deload, but intensity periods work wonders. German volume training never worked, I actually did give it up after the 3rd workout, haha. Also, I did get a nice gain recently after having been doing low volume dc style stuff for a few months. I was able to hypertrophy all those fibers with volume.
To every noob: Overtraining is real. Unless you're that genetic mutant. Pre workout drink, post workout drink, peri workout drink, 400 grams of protein, ZMA, Alpha-GPC, fish oil, 8 hours of sleep a night, caloric surplus, 5-6 meals a day, etc, etc.
Take time off.