The title, "Theotokos," is a Greek word meaning "God-bearer," a name traditionally given to Mary, and it shapes how the whole poem reads. The speaker seems to be in a state of uncertainty, turning over a question they can't settle: could they be pregnant? Something happened "last night," and now thoughts keep circling in the mind.
The second line is the strangest. Doubt acts like water on something iron, which suggests it slowly wears away or rusts what had seemed solid and firm. The speaker's certainty is being eaten at.
The last question widens the poem. "What can I be making / that might know me" could mean a child, but it could also mean any creation that might one day understand its maker. The mood is hushed, anxious, and wondering, with a quiet mix of awe and fear. The short lines and lack of answers leave us right there in the speaker's uncertainty.