Hello, Team AstraQom! Perhaps at a past job you had a co-worker who never took a sick day, especially on those days when they were miserable, sick, and fatigued. It's possible you have even done the same. If you think of those days when you (or the co-worker) went to work when you probably should have called in sick, it is most likely you didn't get much accomplished. Spending the day bundled up in bed not only might have sped up the healing, but kept you from spreading the illness to someone else.
By now you most likely have determined how many times a week, and how hard, you can run. Let's talk about days when the run is on the calendar, but it does not feel like a good day; you're tired, sore, ill, or something important has encouraged you to change your schedule. That's okay.
Like I've said before, we control our schedule and our running; it doesn't control us. You can adapt the schedule by shortening the run duration...twenty minutes (the minimum amount of time for aerobic benefit) is better than no minutes. You can move the run time to another portion of free time in your day.
If it's a question of feeling poorly and you are not certain whether you can run, try what some athletes call the "two-kilometer rule." Begin your planned run course as usual. Run the first kilometer. If you still feel unsure of whether to continue the run, turn around and run the kilometer back to the start point. If you still feel badly when you get back to the start, call it a day. If you feel good, turn around and continue your run.
From experience, I've had track workouts where I felt miserable for the first two or three kilometers of the warm-up, and then something released. I've also had workouts where I called it a day at 3K, rested that evening, then had a great 10K tempo run the next evening.
Sometimes the best treatment for a bad day - or a busy day - is another day. As always, don't hesitate to e-mail me with any questions - firstname.lastname@example.org .