So the Narrator/MC Ayaka has been living bona fide Groundhog Day loops since birth, i.e. uncontrollably repeating a day over and over and over, each loop might contain some minor differences, until there's an iteration fulfilling some unknown criteria, then she gets to move onto the next day and the whole process repeats.
On top of that, she doesn't forget. That itself is already a curse for people in normal timeflow (speaking from my personal experiences of having the "forgetting" function not working very well, my mind gets cluttered and idle thoughts can easily trigger random old unpleasant memories (because the unpleasant ones are apparently tagged "important" and thus exempted from being forgotten) to be dredged up to the forefront of consciousness, and that pretty much destroys my ability to really focus or efficiently recall things I acutally want to recall), but Ayaka here has to endure that multiplied by however many times she has to repeat each day of her 15 years of her life so far. It's a wonder she has not gone insane from all those piled up mental strains.