I have trouble losing weight (even through a regulated diet/exercise), I am always cold (even to the touch), my hair is brittle, and I am always tired. I have Polycystic Ovarian Syndrome , I am taking estrogen/ progesterone for it. My blood sugar levels are normal. I was tested for hypothyroidism but came back with normal TSH levels, though surprisingly I have low Vitamin D and high cholesterol . I am 21 and a female. Why are these things happening to me?