Mary sits in the very back of her high school classroom behind the largest boy in her class, but every time she looks up, she feels like the teacher is focusing everything on her no matter how hard she tries to draw attention away from herself. she constantly constructs elaborate scenarios about what her teacher thinks of her. mary is dealing with

Mary is dealing with "the imaginary audience".
The imaginary audience alludes to a state where an individual envisions and trusts that large numbers of individuals are energetically tuning in to or watching him or her. Despite the fact that this state is frequently displayed in youthful youthfulness, individuals of all ages may harbor a fantasy of an imaginary audience.