Started running, was going pretty fast (probably a bad idea) and at about 1.5 miles, my left calf broke. Decided, fortunately in retrospect, to walk back home. Looks like my left leg isn't recovered from the 12-mile run on Saturday and I may have pushed it slightly beyond what its limits were. Hopefully it will heal by tomorrow. If not, I may have to push the long run (13 miles) back to Sunday to accomodate. Thankfully, next week is a rest week (3-7-4-10).