Suddenly signed out?

[MrWhitticus]

If you have an addon like AdBlock, it can disable your login if that website uses adf.ly or any advertising programs like that, but that would only log you out of smaller venue websites, not anything bigger that that then.

Plus as far as I'm aware the password and login information is stored somewhere other that the History page. Try poking about for them.

Aside from that, I can't help