Judging by the words themselves, the speaker feels crushed by another person's expectations. The "you" in the poem keeps wanting things: for the speaker to be lost, to feel pressure, to be "more like you." Against that, the speaker seems to be slowly giving in, repeating "becoming" and "I've become" as if they are changing without having chosen to.
The title, "Franken Poem," suggests someone being stitched into a shape they never asked for, like Frankenstein's creature, though that is an inference. The speaker calls themselves a "mistake," then "another mistake to you," which hints that the other person's disapproval has become the speaker's own view of themselves. The repeated image of being "under the surface" feels like drowning or disappearing from view.
The mood is heavy, numb, and tired. Short, flat lines mirror that exhaustion. Even the moment of awareness ("I've become so aware") brings no relief, only a clearer sense of being stuck.