Thanks for buying our book and congratulations on diving right into a plan for yourself.
You’re right that you do sound like a text book case of Death by Threshold. Before you begin a new training cycle it is going to be really important to be fully recovered both mentally and physically. Depending on how trashed your legs have been and for how long, you may need more time. You need to feel like your legs are light and bouncy when you bound up the stairs. If there is any residual fatigue then more rest is needed. Overtraining is an insidious condition that can be very hard to shake if you truly were afflicted with it. I’m advising a college ski coach right now who’s top skier got overtrained in late August and has still not been able to come back to training.
Make sure you are out of the black hole of fatigue before you launch back into training!
With your training history and propensity for overdoing it, I’d recommend starting your weekly volume at 50% of your average weekly volume for the past macro cycle of training. It may feel punitively light but it is always easy to increase the training load gradually after a few weeks are under your belt than it is to suddenly find the wheels coming off again 3 weeks into the plan. When that happens that residual/accumulated overload will have crept up without you recognizing it for it is until its too late. The all you can do is stop training and rest. This can create a start/stop/start effect which ain’t a good thing.
So start conservatively, build gradually and pay attention to your body. Then the next training cycle you’ll be a much wiser athlete than the one who just bludgeons himself in every workout.