all of my bookmarks prior to Sept 4, 2026 have been erased. Firefox instructions do not work.

Help! All of my bookmarks, browsing history, and profile prior to Sept 4, 2026 have been erased. Firefox instructions for restoring these prior bookmarks do not work. When I access "manage bookmarks" then the "Library", then "import & backup & restore", there is nothing listed prior to Sept 4, 2026. So there is no file to choose. Also my prior profile has been erased. My profile is completely blank altho I did NOT create a new profile nor did I access my profile in any way!!! Also the instructions for "restore bookmarks from backup" do not work either. I desperately need that browsing history and those bookmarks. I am doing research for an art history project & those bookmarks for the last two years were stored there & seemed securely in place for the last three years. I need those bookmarks & the browsing history which included sites I used but did not necessarily cite in my research. My bookmarks included the sole documentation I had of my research for this project for the last two years!!! When Firefox said it would continue to support Windows 10, I had no reason to believe my entire browsing history and/or my previously secure bookmarks would be erased. Help me restore those bookmarks. dona bretherick