brown fluid but pregnancy test negative

Hi,
Welcome to ehealthforum,
Emergency contraceptives work if taken within 48-72 hours of unprotected intercourse. They help in preventing pregnancy provided you do not have intercourse after taking them. The brown discharge could be attributed to the pill use itself, as they contain high doses of hormones and can result in breakthrough bleeding or withdrawal bleeding. Wait and watch for your next periods. Look out for development of any new symptoms. If you do not get your periods within 10 days of your actual expected period dates, or if you develop any new symptoms suggestive of pregnancy, then consider visiting your doctor/gynecologist for thorough evaluation to rule out pregnancy and to look for any other underlying cause for your absent periods.
Take care.