I have always had irregular periods. The last on I had was 10/11/07. It has been almost 5 months and I have not had a/f. Dr. prescribed Prometrium 200mg for 5 days to help a/f start. It has been almost 3 weeks since my last dose and a/f has not shown up yet. I already took both urine and blood tests to rule out pregnancy. What could be the hold up? Why is it taking me this long to have a period? When I called my dr.s office he said that I needed to wait another month. Please someone with similiar experiances help me.:confused: