Hi, I usually add the non-specific things that happens to me in the notes area. I suppose if you feel tired, you can put it as "fatigue", there is also the "energy" description at the bottom of the FF under Mood/Energy, you can put it as "low". I guess putting it down is just a matter of using it as a comparison of signs/moods/difference from day-to-day. It doesn't matter where you put it, as long as a note is taken. (that's my opinion)

HTH.