You wake up tired. Not the kind that strong coffee solves, and not the kind that lifts after a weekend off. Persistent and disproportionate to whatever you actually did the day before. So you do the responsible thing. You see your doctor. You run the panel: thyroid, iron, ferritin, vitamin D, B12, cortisol, complete blood count, maybe an inflammatory marker or two. The results come back, and the message is some version of “everything looks fine.” The numbers are normal. You a