Maybe God is pissed about no one keeping the proper sabbath. The ancient calendar was based on Moon phases. The First day is the new moon. Meaning they would not fall on the same day of the week every week but upon the New Moon, Half Waxing Moon, Full Moon and Half Waning Moon. It was simplified at some point to be Friday to Saturday. Moon controls the tides of the waters. Hope you live on high ground because the floods are not over yet.