Suggest Remedy For Extreme Coldness When Suffering From Hypothyroidism

I have a hard time regulating my temperature- inside and out. I am always colder than others and am at the point where I may need to where mittens at work! I have hypothyroidism, but they say my medication is adjusted ok. I also notice that if I take my temperature it can be as low as 96.5 and then go up to 98 only hours later. What is happening and what do I do to correct this?