Sorry but most of us need a lot longer than 10 days without running in order to recover properly from racing through ITBS symptoms. Try 3 weeks off then a gentle jog, stop at the first sign of symptoms returning and take another three weeks off if so before trying again. Worked for me anyway after I was daft enough to run the 'last' 13 miles of a HM with severe ITBS pain, and like you I could barely walk after once I finished!
I've just downloaded the Hal Higdon 18 week training program which I aim to start in the first week in December. This leads my up to the beginning of April, so perfect timing.
Has anyone else used this training schedule or done the MK Marathon. Do you have any tips for me?
As others have already mentioned, the schedules are designed to taper at the end so that you peak for the race, so you're best of finishing the schedule on time rather than finishing 3 weeks early and then mincing around with unstructured training for a further 3 weeks. The latter risks either peaking too early and losing fitness or overdoing it and burning out when you should be tapering.
The Hal Higdon 18 week plans work in three-week cycles of build/build/cutback for the first twelve weeks, then maintains and leads into a taper for the last few weeks. If you've got three weeks to spare then I'd suggest turning it into a 21 week plan by repeating any three-week block from the first twelve weeks. Eg if you find the first three weeks tough then repeat those before moving onto week 4. Or if you're already comfortable at that sort of mileage then you could benefit more from repeating weeks 10/11/12 in the middle of the schedule.
Which of the HH plans are you following? There are several, eg I used "Advanced 1", because its starting point most closely resembled the level of training I was already confident of coping with.
I ran well within myself for about 12 miles, could have even picked it up a bit at that stage but didnt because I was running with a friend who was struggling, got to about 18 and hit the wall and virtually walked home. Have regretted ever since not going quicker earlier.
If you were hitting the actual wall at 18 miles then surely it's a fuelling issue and going quicker earlier would simply have left you hitting the wall even sooner!