It seems to be a joke, but it isn't.

I had been using Mozilla Firefox as my primary browser until today. From now on, I'm planning to use Google Chrome as my default browser.

Weeks ago, I somehow logged in SuperUser for the first time via my StackOverflow account in Firefox. Now I'm trying to log in in Chrome, but it asks my email address and I don't remember it.

When I enter my account in Firefox, I see that an email address of mine is listed there (The same address shown for email subscription when I'm asking a new question). But I cannot log in with that mail address. I tried several possible passwords, but non of them worked. I tried recovering my password, but it says "No account with that email was found".

What do you suggest me to do?