At the end of some of my 5Ks I feel knackered, and today I was slower than I have been (although to be fair I have a horrid cough atm)
I wondered if when you build up to 10K, is it the same as it was building to 5K in that it feels manageable or is it a grind? This may be a stupid question but today I can't imagine having run 5K and still having another 5K to go.
Finally ran in the rain today, and it was good, I wouldn't go mad for it but it was a pleasant change.