This could be do to many reasons, including lab error, transient phenomena, possibly related to a recent viral illness. It should be repeated, as your physician has discussed with you. HDL is the good cholesterol, and you want this to be elevated. The HDL should be greater than 45. Regarding your symptoms, fatigue, and intolerance to cold, I would recommend you consider doing Tai Chi or Yoga, working with breath work to increase your intrinsic circulatory status.
Radishes reportedly have a chemical, raphanin, that some day assist keeping thyroid levels balanced.
In addition, the fresh juice of green walnuts can increase thyroxin levels. This information is not a substitute for professional medical advice, and should not be taken as a diagnosis or treatment strategy for a medical or health condition or ailment. You should carefully read all product packaging. Statements and information regarding dietary supplements have not been evaluated or approved by the Food and Drug Administration. Please consult your healthcare provider before beginning any course of supplementation or treatment.