I can relate...
On the 12 mile run I was VERY tired, I didn't imagine a dinosaur, but rather that like a mob of angry people with pitchforks that happened to be olympic sprinters.
I came in at 73:44. I was haulin ass. What can I say. But that was like a year ago. I need to get back into shape... I fell far. Weight lifting caught up to me, and such... I gained alot of muscle and then running go harder.