Hello Lutfah67, You have not given a detailed history of your ailment nor specified your age. However, duphaston is a medication generally used to treat secondary amenorrhoea, menstrual irregularities, endometriosis, etc. You need not worry for bleeding that you are experiencing even if you are suffering from endometriosis as you are already under medications. Backpain is a common feature experienced by most women, it is quite normal. You have been prescribed medications for it. Abdominal pain that you have is known as dymenorrhoea, it is an indication of ovulation ( egg release ) , you need not worry, its quite natural to experience it. Just watch how long you have your menstruation. If it stops in 5-6 days it is normal, if it does not do visit your gynecologist. Your uterus need to be examined clinically and you may need to undergo few blood tests and USG to rule out fibroid or endometriosis which cause heavy bleeding. The bleeding can also be as a result of harmonal imbalances which need thorough study. Since you are bleeding heavily pay heed to your diet, eat green leafy veggies and bananas. These are rich in iron and minerals. Lamb liver cooked well, jaggery food preparations will also increase your haemoglobin ( Hb% ) content and help you feel better.