The 7-day week was introduced in Rome (where ides, nones, and calends were the vogue) in the first century A.D. by Persian astrology fanatics, not by Christians or Jews. The idea was that there would be a day for the five known planets, plus the sun and the moon, making seven; this was an ancient West Asian idea. However, when Christianity became the official religion of the Roman empire in the time of Constantine (c. 325 A.D.), the familiar Hebrew-Christian week of 7 days, beginning on Sunday, became conflated with the pagan week and took its place in the Julian calendar.
Thereafter, it seemed to Christians that the week Rome now observed was seamless with the 7-day week of the Bible -- even though its pagan roots were obvious in the names of the days: Saturn's day, Sun's day, Moon's day. The other days take their equally pagan names in English from a detour into Norse mythology: Tiw's day, Woden's day, Thor's day, and Fria's day."
I am not sure what that has to do with my post. I struggled with the understanding of “Sabbath” all my life, until I observed a real Sabbath with a Messianic congregation and THEN it became clear to me what is the purpose of the Sabbath.
The Lord does not care so much about the legalism of counting days. He gave us Leviticus so we could see what Legalism is about.
Jesus told us to apply the spirit of law to the letter of the law- and love Him with all our heart.mind and soul.
So- see what the Spirit of the Sabbath is all about. The letter of the Sabbath is not going to bring you any joy.
Shalom.