Yvonne - looks like it is the cold weather then as you say, just something you will have to learn to cope with, you are obviously sensitive to it when breathing in alot of cold air, it could be something you get more used to as time goes on, good luck.
Davvy1 - as this will be your first marathon, I would suggest that you have loads of time up until April, and possibly do your training plan from january with the building up of miles, to 3 weeks before race day and then taper. after the half which will be about mid december from what you have said, I would take a week off, wnd just do some shorter runs through the week, then for the weekends stick to 10 to 13 milers until January, and enjoy running, then the training starts. this is only my opinion you are the person that knows you best go with how you feel, good luck.
Week 2 of my training started today, with a gentle 7 miler, heart rate up abit, but the fitness will take a couple of weeks to kick back in, got my new Hoka's last week and so far really impressed.