If you know the email you used then you can click that button called "Members", left to the golden box which says "Registration Closed" and search for the account name by using the email address.
I tried that, and found it, but as far as I can tell it just has the name I set for it, not the actual username. D: Thank you though, that was a really smart suggestion lol
I sent a PM to Ringo, hopefully she can send me the infos or something.