This is the 890th most frequent Turkish word.
gününde
"On the day" or "timely."
Here, 'gününde' is used metaphorically to describe someone's optimal state of being.
Bugün tam gününde hissetmiyorum.
Today I do not feel completely in my own spirit.
In this context, 'gününde' means 'on the specified day or on time.'
Raporu teslim etme tarihi tam gününde yapıldı.
The report was delivered exactly on its due date.
Here, 'gününde' refers to 'during the workday' in a temporal sense.