Is a period considered regular if it comes five days before its due date, for example, if it comes on the 5th instead of the 10th? And is the blood that appears a day and a half after the end of the period considered menstruation, necessitating another ghusl?

If menstruation returns five days before its usual time, after the previous blood flow has ceased for thirteen days or more, it is considered a new menstrual period. Blood that appears one and a half days after the cessation of menstruation is considered a continuation of the previous menstrual period, as long as the total duration of both and the intervening period of purity does not exceed fifteen days. One must perform ghusl (definition) (ritual bath) after the cessation of this returning blood, and the purity intervening the menstrual period for a day and a half is considered a valid purity. If blood appears outside the usual time of menstruation, it is istihada (non-menstrual vaginal bleeding). If the habit has settled on menstruation every twenty-five days, it is a regular menstruation. However, if the matter is irregular, it is not a settled habit.