Recent items, Finder sidebar additions, etc. reset after every restart

This is very strange. All changes I make to the Finder sidebar, Apple Menu Recent Items, Text Edit "Open Recent", etc. ever since a certain point in time (about a few months ago now) are constantly reset (missing, forgotten deleted -- GONE) after every restart. This is getting so frustrating. I didn't know about the Finder sidebar issue at first so I created a smart search folder to include recent apps & documents used in the past few days or so, so that when I lost the Apple Menu and other Recent Items I'd still have the saved Finder sidebar searches. Now that it happened again though, I see those Finder sidebar items are gone too! It's literally like my Mac doesn't want to remember any changes after a certain date in the past (now that I think of it, there were two items that kept disappearing from my Finder sidebar that I had to keep adding back, but I didn't know it was all related).

Is this a PRAM issue? I've run the disk thru Disk Utility First Aid and repaired permissions several times and all is well. Normally I would say there is a prefs or cache file to trash, but if they are resetting on their own back to that point in time trashing them would only make me lose more. In fact, a few weeks ago I saw that my Text Edit Recent Items was reverting to the same state from long ago (documents I hadn't opened in a long time) so I did trash that file. But then it just cleared and now reverts to that cleared state as I explained, not remembering anything I opened before the restart. I do have Time Machine back-ups but I'm not sure that just replacing the recent items and finder plist files will help. How can all those files be corrupt every time. It's more like a whole section of the Mac's "memory" is gone, not just one menu or file.

Can anyone help? I am beginning to dread having to restart now as a result. Thanks to anyone that can help!