Sex glands symptoms and conditions

I started synthroid about 6 months ago and I am unhappy. I complained to my OB about my lack on sex drive. He tested my thryroid and said it was the cause. I have always struggled w/ my weight but had it under control. Since I started a low dose of synthroid, I have gained 4 lbs (I am only 5' tall so this means none of my clothes fit) despite running 30 miles per week and watching my diet. My once thick hair is getting thin and my sex drive is no better. Also, my stomache is often bloated.