Help please!

I am a student and i was working on an assignment and this is the second time this has happened not sure why it did or how it went back to looking normal, but my model is not looking like it should!, Can someone please explain what I did and what can i do to get this to look the way it did. photos attached for reference.

Thank you.

Looks as though you have turned on View/Face style/Xray.

But we could tell with more certainty if you can upload your model .skp file here. Just drag it from File Explorer into your next post. If it is more than about 15MB, use a file sharingservice like Dropbox, OneDrive, or WeTransfer to upload it.

You may have Parallel Projection turned on, try Perspective to make it look more normal.

Also, if your GPU is AMD 6800, make sure you have updated the drivers recently.

This looks more like the driver bug that recently affected other AMD card users.
However, whatever graphics card you are using, now is the time to try updating the driver.

Doesn’t look like X-ray style to me. Clipping it might be.
Looking at the black masses of edges visible here and there in your model (kitchen, TV, lights or loudspeakers etc) you might have added elements with unnecessarily dense polygon meshes, They, too, can cause problems.