Must I pray or stop praying in the event of an irregular period and intermittent bleeding, and must I re-perform the prayers in which no blood was discharged?

If the total duration of the blood is a day and a night, it is considered menses by the majority of scholars, and you should make up the prayers if the bleeding did not reach this duration. Scholars differed regarding the period of purity that intercedes menses. According to the opinion of those who consider it a valid period of purity, you should make up the prayers you missed during the interceding period of purity.