I have just done my first run of week 3.
This is my 3rd attempt at it and this is the furthest I have gotten. The last two times I tried it was winter and I gave up because the ice made it dangerous to run.
Having been a smoker for 13 years and being a serious chubster I never thought I would manage week 1, but I have and though the step ups in the time youre running seem scary at times they are possible so long as you push yourself (You have to have a lot of will power. My house mate doesn't have much so she is repeating week 2 right now as she didnt push herself last week and isn't ready for week 3 as a result). One thing I reccommend is doing the NHS Strength and Flexibility podcasts after the running podcasts to stretch out after your cardio work out! I find that I feel more sore the next day if I dont. Also, drink milk within 30 minutes of finishing your run: It helps hydrate you and the protein helps repair and build new muscle achieved through your workout.
I am happy to be an egger onner if you need the encouragement!