I did a half marathon (well, nearly 14 miles) today, took me a smidgeon over 3 hours, went, stopped, yakked with partners, stopped for a pee, looked at the fish in the canal etc. Finished with a mile or so at 7.5 m/m.
Very sore but a lovely way to spend a few hours with friends.
Think may have aggravated a few injuries and struggled a lot.
A fortnight ago, did 10 miles at a much faster pace, no hurts aches or pains and felt a whole lot better.
The point is, some days you will have good'uns and some days you will have bad'uns.
The bad days are hard but when that one good day comes along, it is worth it.