If that looks really rotten, it's because it is. I did very little running last week due to a combination of reasons summarized as bad sleep, my wife having a nightmare so I stayed in bed to comfort her rather than run, and 2 days of kids up too early so I stayed home so my wife could sleep.
Wednesday evening I ran at the gym. I don't really know how far it was. My Nike+ said 15K+ while the treadmill said just over 5.5 miles. I didn't go the full 6 because we had dinner plans. I split the difference in calibrating the Ipod but that's too fast (clearly given the speed). If I agree with the 5.5 miles that would be 12:30 miles. Not unreasonable.
Saturday should have been my longest run of my half-marathon training. But a combination of big fight the day before, bad sleep, upset stomach, and being in a hurry to get home so we could go out of town cut it short. I ran on the treadmill (different treadmill) and according to that machine I was crawling. If I accept that treadmill's total I ran 7.81 miles in close to 2 hours for a 15:00 mile.
I can't imagine that my speed was that different between Wednesday and Saturday. If I believe that my IPod has been calibrated correctly in the past (I've compared distances to driving my car and once to my wife's smart phone's application) my running speed is between 11:30 - 12:30/mile depending on how I'm feeling that day and run distance. If I say, ok, I ran 12:30/miles Saturday then I ran around 9.2 miles and if I guess slower than that at 13:00 it would be about 8.84 miles. Either way, I didn't do my pre-half long run.
I think what has me so concerned about the calibration is simply not knowing whether I'm doing enough to train for the half-marathon. If I ran 11 miles the past two weeks, I feel good about it but if when I thought I ran 11 miles, I ran ... 9 miles or less, then I feel pretty worried.
This week's schedule is a 6 mile run tomorrow, 6 mile Thursday, and 8 Saturday. Assuming I can run outside tomorrow, I plan to use my new phone to map it on GPS and then calibrate the Ipod to that distance. It should give me a good idea whether my runs have been accurate in the past.