Steph, when I was talking to you at Goring, you and your cough sounded awful, so dont beat yourself up about it. After all, it was only a DNF, you didnt injure your self, the cold/cough thing will clear. Once it does, you will be back training again and next time you WILL get it You've already show you can complete distance, it just didnt happen this time.
I find time in aid stations goes really quickly, and even 5 mins goes fast, so if you have 14 aid stations, thats an extra 70 mins on your time. Having said that the stop does make you feel better. I dont have enough experience to offer sound advice on this, just make sure you allow the stop time while working out your paces.
Good luck with your run and see you at Goring a few times