Icloud Desktop Sync deleted files from my previous Laptop

Hi!

So this summer I got a replacement laptop for my 8-year old macbook Pro. Since then, I did not use my old laptop anymore. However there were still a lot of files on there which I wanted to keep save. Today I turned on my old laptop after a few months of having it off and found, to my surprise, that my old laptop desktop has synced with my current desktop on my new computer. This means that all of my old desktop files are gone. I have searched everywhere (Icloud drive, restore files etc.) but I can not find them anywhere. Does anyone know what has happened? I have Icloud sync turned on, but unfortunately did not realize that it would take files off of my old computer and replace them completely.. Help!