Hello, You are having very light bleeding but blood is dark brown, you are on the last week of the first pack of contraceptive pills. It is just breakthrough bleeding and you need not worry. Contraceptive pills cause changes in the hormonal balance of your body hence you may experience scanty periods, delayed periods or sometimes heavy periods. As the body adjusts with the CP, gradually you will have normal periods or break through bleeding. You are suggested to take the CP as instructed by your health care provider and as written in the leaflet for the best efficacy. Take home made nutritious food rich in calcium, magnesium, iron and protein. Stay adequately hydrated & take quality sleep. Always perform safe sex and avoid multiple partners to prevent STD. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician