The Lord's Day (Sunday) .VS. The Sabbath (Saturday)

Christians are not under the Old Covenant. God DOES want us to only work six days and rest on one day for the well-being of our bodies and minds, but that rest day isn't any SET day under the New Covenant. It was a SET day, Saturday, under the Old Covenant.
It's not a sin to fish, hunt, work or go to the gym in-between Church meetings on Sundays. The Early Church met on Sundays, the first day of the week, throughout the Book of Acts, but they regarded it as a day of fellowship with other Christians, NOT the day of rest ordained by God, which was the SEVENTH day, Saturday.