Memory problems

I decided to memorize the Chopin nocturne because I think it will help the left hand to play the correct chords and also I can concentrate on expression etc. if I'm not trying to read the music. Unfortunately, memorizing a piece is a lot harder now that it was when I was a kid! This is partly because I am trying to memorize this one properly, i.e. actually paying attention to what notes I am playing rather than relying on muscle memory. I think I relied a lot on muscle memory and hand position rather than thinking about the actual notes when I was a kid and this tripped me up under pressure. As my finger hit an F#, for example, my mind would say "I didn't know I was playing an F# there, is that right?" and all would start to unravel. I couldn't look at my music directly before a performance because I would start questioning the notes and it would throw me off. So now I'm trying to think about not only how my hand looks and feels on the keyboard as I play, but what the actual chord is that I'm playing. Seems obvious, but is new to me!