How do you measure productivity?

I don't know whether to count the last two days as productive or not. I did stuff, but they weren't really big stuff?

I'd planned to go for a book launch/signing on Thursday because part of our homework is to review a live literature event. But then after an incredibly full day of classes + Writers series talk + dinner on Wednesday, I just didn't feel like moving at all. So I spent the day mostly in bed, reading Dreams of the Dark Sky, which I'd gotten as an ARC for review. Then I forced...