I promised a quick update after I got back to running. I did 5 miles last night, and it was hard. It feels weird, since just 10 days ago running 10 miles was easy. I'm not really sure why I feel so tired & unable to get into a good running groove. It was a lot hotter & more humid last night that it's been lately, but it seems to be more than that. It's probably just mental - I'm psyching myself out somehow.
Has anyone else had this problem before, and how did you work your way out of it?