The title points to social media, and the poem reads like a short, uneasy reflection on what it means to put yourself online. The opening image is striking: the private self becomes "public as a door," something anyone can walk up to, knock on, or pass through. A door is meant to separate inside from outside, so calling the self a door suggests the line between the two has gone blurry.
The next lines are harder to pin down, and they seem to circle a worry that the speaker would turn into whatever they might do, or whatever they might post. Identity starts to look like a set of actions on display. The abrupt "heaven be off" feels like an impatient wave of the hand, a refusal of some higher judgment or perfect ideal. The speaker settles for something smaller: "let me fit myself." The mood is wary and slightly weary, with a quiet wish to find a shape that is honest and still livable.