Could Loss Of Weight Be Due To Low Transferrin Saturation And Vitamin D Levels?

Since the begining of December I have lost 17 lbs with out changing my diet going 12lbs less then I have ever been since middle school. I am down to 123 lbs and look very sickly. Had blood work done last week and the only things that came up are my transferrin saturation was low at 13% my b12 was high at 878 my Vit D was low at 16.3 and my BUN was 5. They did a thryoid test that came back at .87 but they forgot to tell me to fast and I ate a large bagel loaded with cream cheese and a greek yogurt.