Black boxes & graphical errors appeared suddenly all over my image in Photoshop 22.4.3 on Windows 10

I've had no issues with this project for the week that I've been working on it and suddenly earlier today I was trying to use the fill tool and the area it filled had big white striped squares taken out of it and just looked very glitchy. So un-did it and went in to use the paintbrush tool and it made a white outline over the brushstrokes when I went over an older area of color. 

Then I un-did that too and now it looks like this. I'm not great with technical stuff so I don't even really know where to begin with this. I've restarted Photoshop three times and my whole machine twice. I don't know if it's because I have too many layers or cause the image is so big but I've spent a long time on this and would really appreciate any help on fixing it.

My Photoshop version says its 22.4.3 and here are my computer specs: 

Device name LAPTOP-K68A6RS3
Processor Intel(R) Core(TM) i7-10750H CPU @ 2.60GHz 2.59 GHz
Installed RAM 32.0 GB (31.8 GB usable)
Device ID 6F55B8B0-2D9C-4BD0-9B56-9C00B62496EF
Product ID 00325-81739-58101-AAOEM
System type 64-bit operating system, x64-based processor
Pen and touch Pen support

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