What is the ruling regarding the prayers I performed before knowing that the emission of prostatic fluid (wadi) invalidates ablution, and what is the ruling if its emission was involuntary? And what is the ruling regarding the use of two inner garments, one for prayer and the other for home and sleep?

To overcome waswasah (whisperings/obsessive thoughts), a servant turns to Allah through supplication and remembrance, for Allah Almighty says: ﴿Is not He (better than your gods) Who responds to the distressed one when he calls Him, and Who removes the evil﴾ and ﴿Verily, in the remembrance of Allah do hearts find rest.﴾ Among the ways to repel waswasah is to seek refuge with Allah from the accursed Satan, as mentioned in the hadith: "If you feel it, seek refuge with Allah from it, and spit to your left three times." Another way is to completely disregard the waswasah, for whoever listens to it will find it increasing until it drives him to madness. Its cure is to believe it to be a satanic thought and to fight against it. What also helps in expelling waswasah is: the remembrance of Allah in every state, reciting the Quran, especially the Mu'awwidhatayn (Surahs Al-Falaq and An-Nas), frequent supplication, increasing good deeds, and staying away from sins.