clearing cookies/cache

[BellaUSA]

Windows 8  Firefox
Recently cleared history,cookies. & now my email doesn't automatically appear in address bar. i have to sign in each time. What mistakes did i make, how do I put things back in order ?
Also, have been hearing that passwords made up of a combo of letters, numbers, symbols are no longer as 'safe' as they once were, & that one should use a hodge-podge of words strung together, not necessarily making sense. Which is best ?
Thank you all !

[Mark.]

if you told FF to clear your cookies and history, doesn't that explain why your email address is gone?
either add it as an exception, or bookmark it so you don't lose it again.

as to passwords, bit of a subjective topic, as everyone has their own personal spin on that one.
for me, this sums it up; https://www.xkcd.com/936/