I am 25 years old and in good health. I am on birth control and have been since I was 16 because of irregular periods. I have been on my period for 17 days now and show no sign of stopping. Even when I was younger and had irregular periods, they have never lasted this long. I did take the Plan B morning after pill about a month ago but I took that once before several years ago and didn't have a problem with it. I am getting fairly concerned since the bleeding is somewhat heavy and I am feeling very tired and worn out. What could be causing this and how do I make it stop?