You should expect bad days.
To think that you can run every day and feel great every single time is naive, to say the least.
Anything can affect your running.
Maybe you didn't get enough sleep the night before. Or you had too much dessert. What about that extra beer with friends?
Today was one of those bad days for me.
I woke up. Followed my morning routine (stretching and writing). And then went out for my morning run only to feel tired and tense for the whole 40-minute session.
When I realize I'm not at 100% I tend to get angry at myself.
Why am I feeling groggy and tense if I followed my routine to the letter? Or did I? What changed yesterday that's affecting my performance?
These questions burn through my mind on repeat while I force myself to keep going.
Some days, I'll manage to identify the culprit: "I stayed up late reading."
On others, there will seem to be no reason.
So, while I try to avoid bad days at all costs, I've been learning to avoid anger. I've started to enjoy these mysterious bad days.
They exist for a reason. To help me overcome my limits and keep going.
Some days I may not feel in good form. But I know that enduring such a day will help me improve and be ready for when the next good day comes around!
Just keep running.