Hey teigyr, congrats on the great race!
Don't feel bad about your ranking, look at WHAT you did. I mean, heck. You stomped your previous record by 20 seconds/mile! That's pretty dang good!
For myself, I did a run on Saturday. It was not good. I mean, easily the worst run I've ever done. It shouldn't have been hard, just a nice easy run of 4.5 miles. I've done runs up to 7.25 before without feeling bad, though not since injury.
Maybe it was the heat and humidity, or the fact that I did the run right when I woke up without eating or hydrating before (but I never hydrate or eat before runs <5 miles!), or maybe i'm just exhausted from training. Maybe a combo of all three. But I had to walk, so many times just to finish. Several times I was almost in tears. My legs just felt like lead and I had no energy.
I hate running in the heat, so maybe that was a big factor, but next time I'll make sure to eat and hydrate beforehand, just to make sure I have the energy I need.