What is the ruling regarding Tawaf Al-Ifadah, given that the questioner took pills to stop menstruation, then saw brown discharge on the night of the tenth of Dhul-Hijjah, and then performed Tawaf on the eleventh and saw light brown and red discharge after Tawaf?

Your circumambulation (tawaf) is valid as long as it was performed after you were certain there were no discharges. The presence of discharges after returning does not affect its validity, as there is no requirement to inspect the private parts during tawaf due to the hardship involved. This is if the discharges are considered menses. However, if they are not considered menses, then the tawaf is valid all the more so.