You may be insane and not even know it.
How do you know what you perceive as real is real? One way is to observe the impact on your emotions. If you are not completely happy, peaceful and satisfied your perception has room for improvement. Another way is to observe the relative permanency of what you perceive as real. Anything that can change ultimately is not true, as what is true cannot change. If what you perceive as real can change your perception has room for improvement. If what you perceive as real is not real, then what is real may very well be what you do not perceive.
How can you understand what you currently cannot perceive?
Of yourself you cannot, otherwise you already would have. You first need to receive help to perceive things as they really are. . God, Whoever He Is would reveal Himself sufficiently to you so that you would understand Who He IS.
Isaiah 35:5 Then the eyes of the blind will be opened And the ears of the deaf will be unstopped.
Isaiah 42: 7 to open eyes that are blind, to free captives from prison and to release from the dungeon those who sit in darkness.
Isaiah 42:16 I will lead the blind by a way they do not know, In paths they do not know I will guide them. I will make darkness into light before them And rugged places into plains. These are the things I will do, And I will not leave them undone."