Must I repeat the prayers I performed after feeling madhiy exit and before I was certain of its trace, or should I consider that it exited after the 'Ishā prayer, and what should I do in similar situations in the future?

We ask Allah to cure you of obsessions. We advise you to refer to Fatwa (definition) no. 59951. The certain fundamental principle is that madhiy (pre-seminal fluid) has not been discharged. Wudu' (ablution) is not required unless one is certain of its discharge and its presence on the clothing or body. In such a case, the affected area must be washed, and wudu' performed for prayer and similar acts of worship. You are not required to repeat your Friday prayers for two reasons: firstly, the arousal that caused the discharge of madhiy occurred after the 'Isha' (night) prayer; and secondly, the legal maxim states, "The origin of every event is its estimation at the nearest time." The nearest time for the discharge of madhiy is after 'Isha', especially since the arousal occurred after the 'Isha' prayer.