Why Am I Having Spotting?

I am 73yrs. old, am 5ft. 6 in. tall and weigh 240 lbs. I am type 2 diabetic, am treated for high blood pressure and a condition known as ET, Essential Thrombocytosis. (sp. ?) I also have COPD. I basically do all I want to do whenever I want to do it. I mow my lawn and all the work necessary around my house. The last two days I have experieced some spotting in my underwear from my vagina. This greatly concerns me. What could it be and who should I see about it?