Hypothroid/high cholesterol

I am 31 year old female and recently had a medical and have found that my total cholesterol is 6.4mmol/l and my HDL is 2.43 mmol/l, ldl 3.05, as i am a vegetarian for the last 18 years I was surprised as the only source of saturated fats I have is cheese which I wouldnt eat every day (my total cholesterol was 3.7 mmol/L 2 years ago), I am not overweight bmi of 20 but i do smoke blood pressure is 110/60. I have for many years suspected that I might be hypothyroid and have spent many visits to doctors with complaints of day time sleepiness for sometimes up to a hour at work a day despite of restful or long sleep, I also feel very cold all the time and my body temperature is 36oC, i think its the cold i feel that makes me fall asleep, this a problem Ive had since I was 15, I got my thyroid results again today and they are normal TSH 0.71 and Free T4 14 (9.0- 19.0).  The doctor is wishing me to go on a cholesterol lowing diet, but I thought if HDL levels are high you are ok? I am so sick of being tired and cold please help.

[gimel]

I can't speak to your cholesterol questions, since the measurement units are totally foreign to me.  From your body temperature and fatigue symptoms, I can understand why you are questioning the  possibility of hypothyroidism.  The most important thyroid hormone is free T3.  FT3 is 4 times as potent as free T4 and largely regulates your metabolism and correlates best with hypo t symptoms.  You need to be tested for free T3, along with the free T4 and TSH, in order to determine if this is causing your symptoms.  

[redheadaussie]

Hi, I too was a vegetarian and my total cholseterol was over 5.7 (Australian tests) It shot up to 7 after I had a total thyroidectomy!
  I went on a low cholesterol diet when it was 5.7 at the insistence of my doctor. I told him I had nothing in my diet that had high fats in it, being vegetarian! But I did cut back on cooking oil (mind you I grilled or used the oven to start with in my cooking! no frying at all!) After 3 months it had dropped down to 5.6....aaaaargh!!! But my LDL's the bad cholesterol went UP!
I had my total thyroidectomy and it shot up to totals 7.0. LDL went up again to dangerous levels so I went on Crestor 10mgs daily. This brought me down to 3.7 and good levels of both HDL and LDL...I notice it is starting to creep back up now at 4.5 recently.
  Thyroid disorders often have high cholesterol problems. For me I got the double whammy, family history of both mum and dad's sides of the family, and the thryoid issues. I have Hashimoto's disease.
   My Free T3's are dropping, and as gimel says, the Free T3 is a way of making the body hypo if not enough in your system. I too am feeling colder than normal. My hair is falling out a lot, yet my TSH and Free T4 are totally higher than need be, indicating me to be hyper!
  So, as far as the cholesterol goes, you should give the diet a go, but I think you will be like me and have to go onto medication.
  It's the total cholesterol they worry about, not just the HDL...You can have super wonderful HDL Like I did, but lousy total...they add the HDl to the LDL to give total.
I know you already know this, but if you could cut back on the smoking you will lower the chance of any heart disease, as having high cholesterol and smoking is like giving a baby a loaded gun  in a crowded room....eventually it will go off...
  Good luck!