What Causes Brown Discharge Through Nipple And Irregular Periods?

I am a 41 yr old woman, 5'7" and 152 lbs, I am hypothyroid and TSH level was 8.670, two months ago and had Levothyroxine upped from 0.100mcg to 0.112 mcg. Since this I have had irregular periods ( in fact, twice this month)and noticed that I now have a brownish red discharge from my right nipple in just one spot when I did my self breast exam. I also have been having headaches, more in the sinus area and very dry facial skin. I am up for a mammogram and pap ...just moved to a new state and do have an appointment next week to check my thyroid. I am very worried about this nipple discharge. Could it be a sign of breast cancer?