Replying to Fellow musicians I need help

So I play intermediate to advanced piano and beginer guitar, and as I'm improved my playing a lot over the last few months I've suddenly lost my ability to memorize the way I used to . a year ago I could sit blindfolded and walk someone through an entire song note by note. But now it just feels all scrambled in my head when I try and play with out sheet music. What's weird though is when I do have the music in front of me on a lot of songs I don't really pay much attention to it but, when I take it away I can't hardly play. This is incredibly frustrating so any help is greatly appreciated. plus k