Motivation Sideswiped

I was really motivated and excited to get a run in. I even woke up BEFORE my alarm and hit the pavement by 5:30am. I got about 3 blocks in and BAM... the calf pain. I tried to "run it off" for a couple more blocks but it was getting worse. So I turned around and went back to bed.

Crap. What am I gonna do? How long should I rest this little pulled muscle thingy? It was feeling fine walking, but running hurts. Now it hurts to even walk.