my container tabs are missing this morning

I’d check Firefox’s Containers settings first before assuming the tabs are gone. If you’re using Multi-Account Containers, the tabs themselves may still be open but the container tabs aren’t being displayed the way they were before. Try Settings → General → Tabs and also check the Containers extension if you have it installed. If Firefox updated overnight, I’d also check whether the extension is still enabled. I wouldn’t start reinstalling anything yet, though. That can make things worse. If the tabs are actually missing from the session, check History → Recently Closed Tabs/Windows first.