RE: Distance running?
Was that an all out effort rocky?
I'm not sure what distance the great north run is, is it a marathon? If so you want to be concentrating on increasing the distance you are running, build it up gradually of course, and not too often. For example you could do 3x 6 miles in the week and then a 10 mile run at the weekend, increasing the distance of the long run by 1-2 miles each week, and maybe 1 or 2 shorter runs if you have time, say 3 miles, or even an interval session concentrating on improving anaerobic threshold.