Hi, I Have Had Hypothyroidism For 10+ Years And Have

Hi, I have had hypothyroidism for 10+ years and have been on Synthroid (150mc).Recently my TSH levels have tanked. First .08 so meds were lowered to 125mc..After a month my TSH was barely traceable so now I'm on 75mc for the next month..Meanwhile I had some postmenopausal bleeding so waiting for Vaginal ultrasound results. My mammogram came out with a problem in the right breast so tomorrow I go for an ultrasoun of the breast..Could the Thyroid going crazy be due to a cancer in my body?