I restarted my computer and when I booted Firefox up it looked completely different. I'm assuming they updated, but updates never impacted my settings before and in this case none of my sessions or history is left. I logged in to my Mozilla account and that recovered my extensions, though not my toolbar settings. The real issue is that all of my tabs and windows are gone. In History, "Recently closed windows" is greyed out and Recently closed tabs shows nothing but what's been opened since I restarted. Is there any way to recover my history? '''Edit:''' Resolved: Somehow a blank profile had been set as the default.