I created an account last week, and didn't try to log in until now, but the site says I don't have an account - what gives?

So many people make the mistake of mistyping their emails - gmali.com instead of gmail.com being a very frequent example - and spambots sign up with fake accounts here too often, so we clean out accounts that have never been logged into after a few days. If you log in, even just once, you're safe but if you wait a full week for whatever reason it's likely that your account was deleted with the other dead ones.