The Bible says worship on the 7th day.. and Monday is the 1st day of the week.
Aren't you telling me that you worship on the day of the resurrection of Jesus, which you are claiming to now be Monday?
So go to church on Saturday is that suits you.. Christians celebrate the Resurrection on Sunday.
Didn't you just say that is was 'ok' to go to church on 'Saturday'?
As for Calendrical changes, all of those are accounted for by the Bible, History and Chronologists, and all clearly show that the week has remained the same since time began, for that is how the so-called 'Jews', at present know the 7th day, and how the Christians who keep God's sabbath definitely know the 7th day, and how Christians the world over know when Jesus arose from the dead, being the first day of the week; and how the Muslim population know when Friday is, for each of group has preserved in themselves for the last 2,000 years, (Muslims the last 1400-1600 years depending on one's understanding of the origins of Islam):
God stated the week in Creation (Genesis 2:1-3), and stated it again at the Exodus (Exodus 16; 20:8-11), and again in the days of Jesus Christ (Luke 4), and again in the days of the Apostles (Acts, Hebrews), and again in the final days of John (Revelation 1:10, 10:6, 14:6-7, etc), along with his own Gospel (written after Revelation), as well as the prophets fortelling of the continued keeping of the sabbath, the 7th day, long after the Cross, as Jesus (Matthew 24:20); Isaiah (Isaiah 56:1-8; 58:13, 66:22-23), etc.
Loss of time through Calendrical changes? Are you telling me that God not only lost track of time, or that He wouldn't faithfully remind mankind of the proper time that He set in motion from the beginning? Are you telling me that the population of Jews, scattered the world over on several occasions, all lost tract of when the 7th day was at the same time, or over the centuries (and where is the evidence of this)?, or that the body of Christians (made up of both repenting Jew and Gentile) also scattered the world over, somehow also forgot all at the same time when the 6th day, the 7th day and the first day of the week is? Are you suggesting that the chronologists, among the pagans, heathen, atheists, sea farers, and or Muslims, Jews and Christians, all somehow couldn't discern the sunrise and sunset, then phases of the moon, the rotations of the earth, the position of the stars and the days of the week were so lost as to you (who claim to honour the resurrection of Jesus Christ upon the first day of the week) cannot actually tell, and are now suggesting that the actual first day of the week is Monday (and that you know this, and still go to church on Sunday)?
Are you suggesting that the days of the week, are affected by the days of the month?