Why Am I Not Having Period From Past 6 Months?

I haven't had a menstrual cycle since March 2011. It is now November 2011 and I started spotting (dark brown color) last week, for only one day. Yesterday I spotted a light pink color. Today I had orange spotting. The spotting comes and goes for a couple hours. I don't think I am pregnant. I have had a history of serious pain in the ovarian area, with Doctors who can't find a thing wrong with me. I have no health insurance and can't afford an emergency room visit. Please help.