Running in the rain

Yesterday I ran a 5K in pouring rain. I did OK: I ran it in 22:55, and it was a decidedly slow pace. (All the rain made everyone's shoes more like ankle weights.)

I felt pretty good most of the time, but at the same time I never felt like I had anything more to put into it. I am wondering if all the longer-distance running I've done has conditioned me to running at a slower pace, albiet for longer periods. I never was a sprinter to begin with, but I'm wondering if 5K is now too short of a distance for me to get the engine really going.