No. Douching, when performed normally, should not affect the length/duration of your period .
No. Douching only affects the vagina. The vagina is really a pouch of elastic tissue. At the top of the vagina is the cervix and the uterus. Menstruation comes from the uterine lining shedding and only passes through the vagina. If you are having prolonged menstruation, see a doctor as this can sometimes be hormonal imbalance, thyroid problem, fibroid, polyp or even pre-cancer.