In the end, I could figure out where my tiredness does come from in these days.
In working place, I have been suffered from mental stress by senior colleagues.
It is a simple reason that they really love to interfere with someone.
Now I am the target unfortunately.
This is one of Japanese bad culture and it reminds me of how easy to work outside of Japan except for Racism.
I prefer living outside while feeling like laissez-faire to living here until late 40s.
The life in Japan does not suit me.