Media Library Broken

About a year ago my backup failed to complete correctly, and as a result, it left all my pages filed as posts, both my two separate post types filed as the same default type, and all my media disconnected from the library. I’ve fixed everything I care about but the media problem. The files still exist in my database, and they still show up in my posts, but they don’t show up in my media library. Is there any easy way (please explain in detail as I am not a professional) to get these files back in the library? I don’t want to have to upload them all again as there are many dozens, at least, and they are already uploaded. Thanks for any advice you can give.