The experience of "derealization" is common among those who go through severe anxiety. It reminds me of a poem by Emily Dickinson: "I felt a cleaving in my mind as if my brain had split; I tried to match it seam by seam but could not make them fit. The thought behind I strove to join unto the thought before, but sequence ravelled out of reach like balls upon a floor." "Derealization" means that things around you become strange, unreal, detached from you. "Depersonalization" is closely linked to "derealization." Its a sensation of being outside or detached from your body or parts of your body as if you're doing astral projection or an out of the body exercise. Its a feeling of when you look at the mirror you say its not you! Are you losing your sanity or self-control? I doubt. You are more likely merely responding in your own chosen way to a deep or severe distress.
"Be anxious for nothing, but in prayer and supplication, with thanksgiving, let your requests be made known to God; and the peace of God, which surpasses all understanding, will guard your hearts and minds through Christ Jesus." (Philippians 4: 6, 7)