tough workout

Very tough workout today...not sure why. I did 8 rds of 3 mins, on 1 min off with sword and shield, at a low intensity....working on material from my lesson yesterday with Devon of Acadamie Duello. I was focusing on neural ingraining, and fluidity.  Then i did my long cycle work out. I am focusing on 20 mins of long cycle, 20k, unlimited switches. I may compete at this, at a recreational level. However, from my triathlon experience, I have learned that I like to have some leeway, ie, the ability to go farther than the competition time or distance, so I increased from 20 mins, to 21.  By 7 mins in, my Inner Schweinhund was whining, by 11 mins, he was in full howl.  I had to switch from doing 5 reps per hand to 4.  My cadence was in line with previous efforts, but it was tough not to just put the weight down.  I finished the set, and wanted to just lie down and whine, but instead cooled off with 2 rds of arnis. Not sure what the problem was, the set should have been within my limits, and was, but what a struggle. Maybe i just used up all my focus on the sword.  I feel like it made me stronger to finish, to do the hard thing...but WTF, the human mindbody is a strange beast sometimes.