Wa alaikum assalam,If the bleeding on the 8th day is still part of your regular menstrual pattern, then it is considered hayd and you should not pray until it fully stops.The idea that “period is 7 days” is just a common average. It is not a fixed Islamic rule. Every woman’s cycle is different.Biologically, a normal menstrual period usually lasts between 3 to 7 days, but for many women it can naturally extend up to 8–9 days and still be within normal range.However, if the bleeding goes beyond your usual pattern, becomes unusually long, irregular, or medically concerning, then it is better to consult a doctor. In that case, it may be considered istihaza (irregular bleeding), and the ruling changes — meaning you would pray after ghusl while managing cleanliness.