sudden day of clarity what can it be?

normally my day to day routine is me being frustrated with always feeling burned out because after trying and failing so many times at so many things i always feel like my battery is dead
i have no willpower left to force myself to do any kind of diet or excersise or sometimes even do basic chores until i have to
just constantly feel mentally exhausted.

then this happpens few times a year and it lasts about a day or sometimes few days or maybe a week at most and fades away
and i end up trying to figure out what caused it and why i even have it

so what happens is i would snap into being a comlpetely normal fully functioning human being
i feel normal
i think normal
i interact with people like i have great people skills
i can plan
i can eat properly and have no cravings for crappy food
i go to gym and work out and not drag myself there

pretty much i switch to being a perfectly normal fully functioning person and then it fades away and im left with bunch of memories of what i could be and no answers to why or how it happens
it happens consistently and randomly throughout the year
it happened about a week ago

i woke up and had to chose between going back to sleep or getting up and being productive.
normally that choice alone would drive me crazy and i would end up spending another hour fighting myself frozen by indecision and get frustrated
but i had no problem making the better choice and didnt feel any resistance to making it like usual
and the rest of the day was one of those good days
next day i was back to normal

so i literally described the movie limitless when he woke up next day off nzt it happens to me in real life..
i dont use drugs btw or drink or smoke
i drink coffee that is by my own choice the one bad habit i use to replace few others that were more damaging