The statement "Using Chat has worsened my analytical writing so much. I am cooked for English prelims" suggests that the person feels their reliance on chat-based tools (like AI or messaging platforms) has negatively impacted their ability to write analytically. As a result, they feel unprepared or in trouble ("cooked") for their upcoming English preliminary exams, where strong analytical writing skills are likely essential.
They might be concerned that relying on quick, automated responses has hindered their ability to think critically and develop well-structured arguments on their own.