Visible layers (and entire canvas) not showing

Any advice on the below? 

I was working on a doc and was messing with different ways to make the text appear darker. I tried adding a 3D effect, but didn't really see much change so I reverted, but my canvas was left looking very strange. None of my layers were visible and my canvas became gray with a black rectangle in one corner. I did NOT save, just quit out, and re-opened my previous save of the doc (before the 3D). The gray and black is gone, but none of my layer contents is visible now! My artboard is just totally blank. I even closed this and opened the original document I started from, which was just a template for layout out my book cover- still not showing visible layers. 

A previous post about this error said to check the legacy under preferences-performance, but that is no longer an option. I have totally closed photoshop and re-opened, still not fixed. What can I do? Im running the latest opdate- 22.5.1