What is the ruling regarding the prayers and fasting performed by a woman during a period when she was unaware of the rulings concerning purity from menstruation, and what must she do?

If a woman becomes pure (tahirah) before Maghrib, she must pray Dhuhr and Asr according to the majority of scholars. Similarly, (she must pray) Maghrib and Isha if she becomes pure during the time of Isha. However, you may adopt the opinion of those who do not obligate both prayers. For the future, it is more cautious to follow the opinion of the majority.

If a woman menstruates during the time of prayer, the fatwa we adhere to is that she is not required to make up (qada') the prayer, even though making it up is more cautious. You may adopt the opinion of those who do not obligate making up the prayer if the situation occurred and it is difficult to rectify.

The woman is mistaken regarding the ruling of purity. The default is the continuation of menstruation, and its end is not confirmed until dryness is verified by inserting a cotton swab or similar, and it comes out clean.

It is clear that you were afflicted with some form of waswasah (obsessive whispering) or ignorance during that period. In matters of differing opinions, you may adopt the easiest one. Many scholars believe that whoever omits a condition of prayer due to ignorance is not obligated to make it up.