[drmike]

Just another thing to consider – are you planning reduced volume weeks, and how often? Last winter I had a similar experience to yours – feeling great for a few weeks then crashing, over and over.  I was using an Uphill Athlete marathon plan that had a 50% reduced week every 4th week, but by the middle of the 3rd  week in each cycle I was really struggling and started skipping workouts or getting sick/run down. My takeaway was I needed to shorten the cycles, do 2 weeks where I increased the volume then 1 week of reduced/recovery.  For whatever reason, the 3-1 didn’t work for me and 2-1 was what my body responded to.

Mike