Loving c25k, loving the support and input from this community...BUT... Seems like a big jump up from week three to week four?
I found w3r1 tough but okay and it did get easier through the week BUT it was only 9 mins of running and week four is 16 which seems daunting?
I know lots will say 'it's fine' 'you can do it' etc and,for that, I thank you, but any practical advice/input would be very welcome too 
It's fine! You can do it! 
This was the week (just last week) that I found it start to become more mental than physical (although I don't think Laura says that until wk5d1, iirc).
I did this run once on the treadmill, once outdoors and then again on the treadmill. I was focussing on my breathing, particularly the out breath, visualising, to some degree, my body as a machine - sure legs are running, but what is the chest doing? Every out breath is getting rid of CO2 (the waste), which is good, and the in breaths complete the cycle, ready to expel more exhaust - I was focussing on getting nasty CO2 out efficiently, relax my necking and not trying to blow it out the mouth with puffed cheeks, just letting it come out the exhaust without any back pressure.
Whatever the breathing rate, I realised that I was "stable" - I had reached some level of effort and wasn't starting to expire and my chest/neck was relaxed - I was truckin'! At whatever pace you find comfortable, it's simply oxygen in, co2 out (broadly speaking) - that's about all you can do to help yourself - to keep the machine running.
So in getting through week 4, I focussed on breathing - breathe deep, don't chest-breathe and you could try visualising getting the CO2 out efficiently - I think you'll soon realise for yourself that "it's fine" and that "you can do it".
The halfway point of a week 4 run seemed to come around quite quickly for me... enjoy it while it lasts!!!
Excellent advice. Sounds very sensible. I will try and then report back on Sunday.
Hi thanks for asking! I am not sure I am putting responses etc in the right place but I posted this earlier ( in the question section- which it isn't !) thanks again.
"Had been worried about this due to step up from 9 mins of running, with lots of gaps, in week three, to 16 mins with less downtime in week four.
Then with great help from fellow posters I started to look forward to the challenge BUT woke with a sore foot ( ??early gout which I've had before) So, I left it till the afternoon took some anti-inflammatories - felt a bit better -so I went for it and managed it! Really chuffed.
I used the advice about making lists and blowing out bad air (thanks guys) and although it was hard it was 'do' able and feel great for having done it.
Not sure if foot too happy though!"
Just take it slow and steady listen to Laura and do exactly as she says Try not to think too much about the extra mins you'll be running and try and relax I often make up list in my head Eg what I have to do today or what going to have for tea Really just anything to take your mind of time Also remember back to wk 1 when you possibly thought you would never be able to run 1 min and today you did 9 mins The prog is designed to let you progress so have confidence in yourself and Laura
I always had huge fears before the step ups in runs and I just gave it a go and pushed hard from deep, and when I achieved it, there is no better feeling...and that is so addictive. Well done and enjoy!!
Don't be scared of any run......that is negative and will not help. Start every run with a positive attitude and a smile,"Here I go again, hooray!!" is a good way to start. If you can't finish a run, then there is no shame in repeating it until you can. But more than likely, you will pleasantly surprise yourself and prove again that C25k is a well structured training plan, by completing the run. Good luck
Keep running, keep smiling.
Week Four Day 1
Help Re-doing week four
Just finished day three/week one of C25K (yay me!)
Week Four 
