I Had My Left Thyroid Removed In Jan 2014. Since

I had my left thyroid removed in Jan 2014. Since then every six months my levels have changed and my mess have changed. I went from 137 to 150 to 137 and now on 125. I find myself tiring easy, feeling cold and can't loose any weight and I do not eat much. Is this normal or does my primary care (nurse practitioner) not know what she is doing. Should I go back to my surgeon and discuss this or is this normal.