Great to see your getting out on the bike Carl. Gotta agree with Suffolk here. Time in the saddle is probably the best thing here. Averages are all very well and good, but weather, road surfaces and terrain all play a major role.
I now have a mild form of what your describing cookie monster, although it was acute at one time. I am unsure what it is and really am looking to get it sorted out once and for all. It aggravated by hills and uneven surfaces. I will try and find some answers and post them.
The weathers hopefully going to get better and the days will be longer. So, put two bottles of carb drink on your bike, lash some nana's in the rear pockets with a couple of pieces of fruit cake, get a map out and got out for long rides at the weekend @ level 2. Stop off at a cafe, ride with a club. If you stack the miles in like this, you could actaully enjoy training and meet some good people.
Cause I was a roadie in the biking world, I suffered from poor running mechanics and have had to take 6 paces forward and four back at times. It does however come in time, although I am prone to injury.
Have a glance at your diet. After the hard days, up your protein consumption and listen to your body. Look towards complex carbs for energy, take a multi vit like Solgar VM75. Have a recovery drink on hand and get good quality sleep.
Try to chill and build up the running distance slowly again as I think drop out date is mid-May - which in training terms is a while off.
Take Andy's comments on board re going long and keeping it there. Build up to it though. I hope you recover in time to continue as you seem to have put so much mental and physical energy into the event. Setback are bad, but we can learn from them.