abnormal vaginal bleeding

I am a 22yr old. I had a miscarriage in June of 2006. Ever since I have had regular menstrual cycles with ovulation, but the only time I do not bleed is during ovulation. Usually it is just spotting, but sometimes it is more like a light period. The color varies from bright red to brown. I have had blood work done...all was good, a pap smear done...all was normal, and an ultrasound done. The lining of my uterus or cervix (i forget which) is not quite right. I was put on progesterone for several months, but it did not help. I am afraid to go back to the DR because at this point I have no insurance. Could anyone qualified please tell me what the next step to take would be? I am really desperate at this point. Thank You