Is it permissible for me to fast if I become pure from menstruation in the first week of Ramadan, then after five days of fasting, menstruation returns?

If the bleeding recurs before the minimum period of purity (13 days) has passed, then if it is possible to combine it with the previous blood such that the total of the two bleeding periods and the interval between them does not exceed 15 days, then it is menses (hayd). If the total of the two bleeding periods and the interval between them exceeds 15 days, then it is irregular bleeding (istihadah). If it is menses, then there is no fasting or prayer until it stops and you perform ghusl (ritual purification bath). If it is irregular bleeding, then you pray, fast, and do what a woman with irregular bleeding does.