What about the rest of your profile? Settings, bookmarks, history, passwords . . . .

Look on your desktop. Do you see a folder called; Old Firefox? Look inside. Look for the folder with the latest creation date.

https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles

https://support.mozilla.org/en-US/kb/how-run-firefox-when-profile-missing-inaccessible

https://support.mozilla.org/en-US/kb/recover-user-data-missing-after-firefox-update

Thank you so much for your input FredMcD.

I had tried the "old profile" thing but was unsuccessful.  However, even though I don't have a Library button or an icon to move bookmarks to the sidebar, I just happened to click the quick access "Manage bookmarks button (in blue) and WELLA!!! there's all my bookmarks on a page titled "Library"!!.  I don't know what's going on, but I am so relieved to get my bookmarks back.  I am going to get a thumb drive and download them ASAP.

Again, thank you so much.

D

Glad to help. Safe Surfing.