A day of rest and contemplation does not have to come from God to make sense, but trying to transfer my 2006 self back to the 13th Century B.C. it's utter genius... regardless of whether the creation week ever happened or not.
It is interesting that you came to this appreciation through an experience of overwork. And that said overwork was a consequence of being in debt. Both matters are important to the sabbath.
I said that the Sabbath was about more than counting days. It is also about more than taking some time to rest and contemplate and appreciate creation---although it is all that too.
But even more than taking time off, Sabbath is about
giving time off. That is why the full command specifies that not only "you" but also "your ox, your ass, your handmaid, your bondservant" shall not work.
The Sabbath command is a protection for the vulnerable, that they shall not be forced into continual drudgery by demanding employers.
Sabbath is also about freedom and equality, including a fair distribution of economic resources.
For Sabbath also applies to years and cycles of years as well as the weekly cycle of days. So the land is also to be given rest every seven years. And that offers as well a year of rest to landless labourers and to the beasts used in pre-mechanized farming.
Interestingly, part of the Sabbath year command was also to release debtors from debt and debt-slaves from bondage. So Sabbath connects with the liberation of Exodus as well. (In the Deuteronomy version of the ten commandments, this is made clear, for instead of connecting Sabbath with creation, Sabbath is commanded in commemoration of the Exodus.)
The most complete and radical of the Sabbath provisions was the great Sabbath year known as the Jubilee, to be observed on completing seven cycles of Sabbath years i.e. one year in 50. In addition to rest for all, including release from debt and bondage, the jubilee year was to see the restoration of all land sold in the last 50 years back to the original owner or his heirs. This was a powerful provision against the accumulation of wealth in the hands of a few while the many lacked access to the means of production.
Above all, Sabbath is about trust in God's provision for us. To abstain from planting and harvesting in a culture dependent on agriculture is a huge risk. What is the farmer to live on if he does not plant? How is the landless labourer to live if the farmer does not need planters and weeders and harvesters?
The biblical answer is simple. Trust that God will provide. In the non-Sabbath years God will provide the farmer enough to store and carry him through a Sabbath year. In the Sabbath year, the farmer is to open his gates and make his fields, vineyards and orchards available to the landless (and even to the wild animals) to gather what grows of itself, while he and his family eat from their stores.
Trust in God's provision is the antidote to the greed that says we must always be busy accumulating more wealth. And it is a salutary reminder that no wealth, no matter how hard we have worked for it, comes from our own effort alone, but from the natural resources provided by the Creator.