I have been following SoM for the summer with everything going well. I have been consistently building my mileage and have felt pretty good for the past 4 weeks. For the past 3 weeks (it is a 6 week course) I have taken an advanced course from 7:30-1:30. I have been running 50 mpw which is the most I have run since last summer. My morning runs were generally 5-6 miles easy-moderate or easy, unless it was a tempo, long run, or repeat day. The evenings were some 3-4 mile runs by feel.
This week I started a down week (35 mpw) due to some very mild lower interior shin pain and lack of a lower mileage week since track season. I feel more tired this week than when I was waking up at 5:00 to run every morning. Any reasons for this?