I experience a very similar thing. You aren't alone in being able to look at meta-states of your mind and realize it's different, or things are slipping.

For me, I noticed I no longer had instant recall of various remote control buttons. Was a small thing, but until that time, I stored maps of buttons and modes for everything. Now, I sometimes do, but I find I have the general rules, and need to parse devices and apply them now, not just thought as action as it was before.