OK, Just got back from W6D1..... I was really looking forward to it, got a good nights sleep, got out there, and BLAH......
It was pretty hard, it was mostly fatigue that affected me.
The important thing is that I finished at least. 
Anyway, it might be a good idea to check your soles of your shoes, especially those of you in weeks 5-9.
It will give you a good idea of where you are landing, and if you need to make any changes in your running form.
You should have most of the wear in the front center of your soles, not your heel area.
Take care, and HAPPY RUNNING!!