The stress of the previous weeks would have an effect and possibly enough for the result you got. I had a stressful 5 months with an ill relative culminating in the funeral 2 days after my A race, but when it came to my A race I ended up as DNF and I am now recovering from chronic fatigue, so take care.
Nice going DB, good to have a goal. I have not entered anything but may do a parkrun just so I can have a positive end to the year.
I have enjoyed the sunshine and been out for a pootle on the bike. Managed an hour at 12.6 mph so not too shabby for me, it was on a fairly flat route but definitely my limit at the moment. My garmin effort reading was 4.9, apparently 5 is over-reaching, so need to take care.