I Had My Thyroid Removed 1 Year And A Half

I had my thyroid removed 1 year and a half ago. I was put on 112 mg of synthroid. i recently went to the doctor and he lowered my level to 100 one day and 88 the other. My mother had open heart surgery and I am under an extreme amount of stress. All of a sudden I am getting a rapid heart beat and high blood pressure. My doctor is concerned because he says I have way to much synthroid in my body.