A stupid place for a wall.

After the good run in Bohermeen, I had hoped to build on it.
Monday was a recovery day, heard somewhere that running an easy five miles usually works for a recovery run, so I did 6 on grass.
It worked well and I felt comfortable after with no soreness. Tuesday was rest day, Wednesday was 10 miles at what was to be an easy pace, and without paying attention to the watch averaged at exactly 7min miles. This was faster than expected, and if put it down to the legs still in faster mode from the Sunday run.
Work commitments meant I didn't get out for my planned 9 mile tempo, so I decided to bite the bullet and set out for 20 miles on Friday on what was a beautiful day. The plan was 7:25 miles, and the first 10 went very easy. I had positioned some drinks out on my route, water first, then some sports drink, with water towards the end. Owing to an enroute phonecall, i misplaced the sports drink bottle at 11 instead of 15 miles. The going got very tough after consuming the sports drink. I found it difficult to get a rhythm going, my breathing was slightly laboured and I felt the energy being sapped from me. At 16 miles I slammed into the wall and had to just stop and walk for a half mile. I got going again, did 1 mile at 8:10 and walked the last half mile home having cut the route short.
The 16 miles were exactly on pace. So was it the sports drink, or did I push too far too soon too hard after Bohermeen? Whatever it was, it has hit the confidence big time. Saturday was 6 easy, and today was 10 at 7:25 again, which felt decidedly slow and very easy to finish.
With not long left to London, it is a bit late to be establishing the formula for success! The next few weeks will be crucial. However it goes, I won't be pushing it for any PB's.