Don't worry, it'll probably come to you if you persevere hard enough. I have an extraordinarily good memory usually too, but man, when I was trying to memorise 3000 words worth of essay and creative for my English Ext final, I didn't retain any of it whatsoever albeit going over it for the entirety of the 24 hours prior. I literally thought I was so fucked, but I kept trying and trying and ultimately gave up the night before because I felt so helpless. Then, the morning of the exam, I went to the library to try rewrite it and literally everything came to me without an issue and I wrote out 15 pages without missing anything. It was super weird because literally the night before, I couldn't even remember the first sentence of my paragraphs lol and I was stressing so much about it. I ended up, obviously, being fine in the exam. But yeah, keep writing and writing; it almost never fails. Good luck!
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