Hi joewho, glad to see you on Mozilla Support Forum.

If you registered to Firefox Sync you just need to log in to sync again. If not, there is a tiny and improbable but possible chance to recover your bookmarks and tabs. The idea is to recover the files used by Firefox with some recovery tool like Recuva, EaseUS Data Recovery or Active Undelete.

The files you need to look for are sessionstore.js, recovery.js, recovery.bak, previous.js, places.sqlite and bookmarks-{date}{random}.json. There might be several of them. The first four correspond to current session (opened tabs and windows) and its backups, and the previus session. The file places.sqlite contains the bookmarks and the files ending in .json with name bookmarks + some date + random string contain bookmark backups. If you are lucky enough to retrieve those files copy them on a clean Firefox profile and replace any existing files.

If it doesn't work, then feel free to ask in Reply Section. Thanks for raising your question in Mozilla Support Forum.

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/how-run-firefox-when-profile-missing-inaccessible

http://kb.mozillazine.org/Profile_folder_-_Firefox#Navigating_to_the_profile_folder

https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles

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

Type about:profiles<enter> in the address bar. How many profiles are listed? How many should be there? Also, open the profile folder in your file explorer.