Hi Jo!
There's no shame in repeating a week if you feel you have to - don't worry, you'll get there eventually and when you do, by God it'll feel good! 
Have fun. 
I am on week two and seem to be getting worse. My shins are really hurting and always out of breath. I want to give up but don't at the same time. Any tips please help.
Have you had your gait tested to see the type of shoes you need?
As for being out of breath - remember, this isn't about speed at all so go as slow as you need to. It will get better - I remember when I used to look at the plan and think 'five minutes?? I'm never going to be able to run five minutes continously!' Now - admittedly before my recent knee annoyance - I've done nine miles - that was around one and a half hours continously. 
Edited: 22/07/2012 at 23:54