This is the 2192nd most frequent Portuguese word.
preocupa
"Preocupa" means "worries" or "concerns" in English.
In this case, 'se preocupa' is used in a suggestion or imperative form to advise someone not to focus their concern on minor issues.
Não se preocupa com coisas pequenas.
Don't worry about small things.
In this sentence, 'se preocupa' is used as a reflexive verb to convey the act of feeling concern for her children.
Ela sempre se preocupa com seus filhos.
She always worries about her children.
Here, 'me preocupa' is used to express that the subject (the exam result) is causing concern or anxiety to the speaker.