I'm sorry to hear about this. It sounds like you enabled the automatic computer backup feature in the Dropbox desktop application. Could you first try disabling the computer backup from Dropbox using the steps in the above article to see if this helps?
Afterwards, you can move the folders and files back to their previous locations, which will also delete them from the Dropbox account online.
If there are any deleted files, try recovering them from the Dropbox site.
If the missing files weren’t syncing to your account, then it wouldn’t be possible to recover them from the site. However, it might be possible to recover the files from the local machine from the recycle bin, or using a third party app or service to do so.