The reason I don't plan on running tomorrow is because I colored my hair and I don't want to stain my new white running hat.
Today's 5 k run was just awful. It was cool(er) and not too humid, but I just couldn't keep my feet moving. And it showed up in numbers. The pedometer function on my mobile phone showed I'd run quite a few more steps than usual, even though the distance was the same.
So it's off to bed and we'll see what tomorrow (or the day after tomorrow) will bring.