I think I could say that sanctification is the process by which God 'makes saints' who will follow Him according to the testimony of His Son, Jesus Christ. He leads these out from traditions, and that which is called wisdom, and shows what it means to bear His reproach. It is the process by which one is conformed to the image of God's firstborn, Jesus Christ.
"Therefore Jesus also, that He might sanctify the people with His own blood, suffered outside the gate. Therefore let us go forth to Him outside the camp, bearing His reproach." (Hebrews13:12,13)
Sanctification is the process for making of saints who confess that Jesus Christ is coming in the flesh. When water lines break, the servicer of the water declares that the water user should boil it, until further notice, to destroy any contaminates. How God sets us apart is in His hand - and 'all things work together for good to those who love God, to those who are the called according to His purpose': conformation to the image of His Son! Your setting apart is in His hand until further notice; and you can trust Him, as you have already experienced in a measure.