No i reassure you, if i'd played in one big session i would have kept the letters in mind and eventually try to see if those letters could get something if forming a word.
As I said my main problem was that i had played 2 hours this day, then 2 hours that day, then 3 hours this day, and mixing playing this game with another C-Rpg i'm playing a lot and forgot the letters. I still remembered the first one because it is an enigma i read in another game and by association, remembered the other i spoke of because it came back to me; bot the two others were totally gone.