Missing (Lost) Tables

Has anyone ever seen this before?

I have an Excel doc open. I close the lid, do some other things and come back about an hour or so later. The Excel doc is still open but all of the tables have disappeared. Like, every. single. table. The data is still there, but the tables are not and the name manager is empty. Which means all my formulas that referenced the tables return errors because the named fields they were referencing have disappeared (replaced by #REF!).

The document in question is set to auto-save. There is no option to "undo" or "redo" (the tabs are grayed out).

My version of Office is 2016. My system is Windows 10. I usually leave my laptop on, turning it off about once every two to four weeks, to run updates. When I close the lid, the system is set to "sleep." I've noticed that, occasionally, the system will . . . do something else when I close the lid; I say this because, when I open it up, some of the apps have shut down (like, when I restart the browser, it reopens old tabs).

I store my documents on the cloud (with a local setting for this one computer) since I have three laptops that I use; this one, a tablet (Surface) and a work computer (which I rarely use to connect to personal files).

Is there a way to fix this and get the tables back? Or do I have to manually recreate them (and fix the associated functions)?

I thought as much, figured I'd ask just in case.

Thank you for the feedback.