Newbie with Calves that Hurt

Hi-
This is my first post. I've been training up for a race in late February, a 26 mile trail run. I've done some pretty long adventure races (24 and 32 hour), but never a dirt marathon or ultrarun.

My calves are killing me! Not as in "oh no, I've snapped something" pain, but just darn sore. Is this normal? Am I doing something wrong? Ideas?
Thanks-Darron