In all your cases you need to start stimulating your memory, try to learn a poem or a song or two every week, take cod liver oil every day, add some salad to the burgers.
As a workoholic I had about four years when I would drive somewhere, go somewhere and have my mind pre-occupied with something else to the point of completely not remembering entire days. Even worse - three years ago my girlfriend organized holiday on Isle of Wight for us and I have pictures of it, souvenirs, tickets, the whole nine years and I DO NOT REMEMBER A SINGLE DAY of it. Not a room, not a building, not a single walk, driving there, spending time, partying there, nothing. And so one day I sat down and realized - if you don't remember what you were doing because you were tired, preoccupied and thinking of something else and you don't remember what you were thinking of either then you're just stealing time from yourself. Live it. If you drift away during journey then change radio station, sing, think of funny stories to write down, learn italian from CD. If you drift away everywhere else then refurbish your life, go bunjie jumping, sky diving, wake up. Just so you can say in few years I know exactly what air smelled like, I know exactly what she was wearing and I know exactly how it felt rather than.. amm.. what were we talking about? And how did I get into this thread...