What Causes Frequent Bleeding & Spotting?

I've been on birth control 4 about 5yrs. I have hep C, I have neurothopy ,fybromyalgia, & deteriorating discs in my back. Health dept won't let me take my birth control pills because of my problems w/paralysis in my ft.(Ft drop),they are worried about blood clots. I've been bleeding on & off significally ever since I stop my bc pills. I bleed every 2wks like a menstrual cycle & spotting in between. Do u think. I should be worried it's from my female organs or any of the other medical probs? Susan Fox