How do we possibly know which day of the week it actually is after 1000’s of years?
We do know, because the Apostles, all Jews, would attend the synagogue on the Sabbath, and then they would celebrate The Lord’s Day on Sunday in little house churches since Christ has risen from the dead on a Sunday.
You look on the calendar. We have calendars that go back to the time of Moses. This is really a weak argument. If there was an error, Jesus would have corrected it in His life here. You can follow Catholic tradition or follow the life of Christ who kept the Sabbath. Your choice.
If you observe a Sabbath, with a Jewish congregation- even just once, you will understand much more.
seriously? You think the entire population of Earth might have just simultaneously forgotten what day it is?
:-)