Everything we do has some sort of pagan origin. The pagans and the Jews/Christians have swapped traditions back and forth since Adam and Eve. Nothing new is under the sun.
That's my opinion of the whole mess. We can't change the fact that the days of the week, months of the year, time calendar, and everything else we do originates back to a pagan custom.
So I'm going to live my life unto the Lord, redeeming the time, and the days for Him, in all I do. Every day is the Lord's.