Must one fast and pray during the first five days in which blood discharge is intermittent, given that the normal menstrual period begins thereafter and lasts for fourteen days?

If the drops and bloody discharges continue for a day and a night, then it is menses (hayd), and you must refrain from what a menstruating woman refrains from. If the total of these days, along with what follows them, exceeds fifteen days in a month, then any excess is considered blood of istihada (irregular bleeding). In this case, if you can distinguish menstrual blood, then act according to that distinction. If you cannot distinguish, then refer to your previous habit, which is seven days.

However, if the drops along with the discharges do not continue for a day and a night, then it is blood of istihada and not menses, and you are obligated to pray and fast during these days. Your habit then becomes fourteen days only.