Were yyour original bookmarks preserved?

If you have sync, and there is a problem anywhere, Shut Down Sync Immediately On All Devices to prevent the problem from spreading. Once the problem is fixed, perform the same repair on all computers/profiles before using sync again.

[v57+] Places Maintenance is built into Firefox.

Type about:support<enter> in the address bar.

You will find Places Database near the bottom. Press the Verify Integrity button.

When done, copy and post the results here.

https://support.mozilla.org/en-US/kb/fix-bookmarks-and-history-will-not-be-functional

Were yyour original bookmarks preserved?

No, I no longer have any bookmarks in the bookmark folder. The row above the page display (right under the address bar) that used to display some of the bookmarks has even disappeared. It's like the bookmark function has just completely disappeared.

If you have sync, and there is a problem anywhere, Shut Down Sync Immediately On All Devices to prevent the problem from spreading. Once the problem is fixed, perform the same repair on all computers/profiles before using sync again'.

I don't even know what sync is. How would I find out whether I have it or not?

Sync is an option to share profile data with other profiles and systems.

Sometimes when using refresh, data gets screwed up. That is one reason the original profile is moved to another location.

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