Don't sweat it, same thing happened to me on the second day of US Classic Champs the weekend before NAOC. Every once in a while the body just says nope we're done here. The good news is it's just a fluke outlier; I'd say your true Long fitness is more along the lines of Canadian Champs than NAOC.
Thanks mate! Missed you this weekend at BC's, hope that knee gets better quick
I agree with Will. You have bucket loads of talent whch you have shown e.g. at COC. I'll add that with a better base and more consistent training also comes more consistent performance. Hint! ;-)
Trust me, less halfway through that race - I got the hint ;)