Every line of "I am" begins with the same words, and that repetition is the point. The speaker keeps trying to define themselves, but each attempt ends in absence: no light, no hope, no end, no one to listen. The mask of the opening line is the central image. It hides the speaker's feelings, but it also seems to trap them, since the darkness lies behind it and the heart is "chained."
What the speaker feels is a mix of loneliness, frustration and resignation. They believe no one will understand them or hear their story, and they admit to a "foolish, contradicting pride" that may be part of why they stay hidden. The phrase "hide and seek" hints at a wish to be found alongside the fear of it.
The mood is heavy, bleak and quiet. The closing question, "Who am I?", is left unanswered because "the answer has been long lost," so the poem ends in uncertainty rather than comfort.