Help! Admin permission revoked?

I got a new error opening Indesign yesterday, that said I did not have permission to access the preferences folder.

No biggie I thought, so I went to the library and opened the info on the folder to give myself permission.

I was able to unlock the lock but strangely enough, my username as admin is not on the list. It does have system (read & write), wheel (read only) and everybody (Read only).

Concerned, I went to the library folder to look at the situation there, and it was the same. My username as admin is not listed. Interestingly, on unimportant folders like 'pets' I do see myself listed as a user and I can change permissions there.

I created screenshots to document this challenge to put in front of the community, but everytime I try to upload an image here through chrome browser, it crashes. There are a few other funny things going on, like a trash can that is reluctant to get emptied, and the preview of downloads in my dock only shows an outline of files where it usually displays small thumbs. I just got back from a holiday break and I seem to remember I upgraded to High Sierra just before we left, so I am wondering if something went wrong there.

Any tips would be highly highly appreciated as I live in a remote area with no genius bar around and I have to make a living using Indesign so not being able to access it is a big deal... Thanks!