Help, I'm really freaked out?

[Small town girl]

I was on Facebook and I was doing a quiz, but I accidentally clicked on something else (it was one of those advertisements where it makes it look like your submitting your answers for the results or something but really it's something else, because the real sumbit answers was below it) and I clicked on it and it some how signed me up for myYearbook???!!! what is this??? it looks horrible and i dont want to be on it anymore, but when i click deactivate my account and i use the email and password I used for login on facebook it doesn't work! help, i don't want to be stuck on it since it looks dodgy. please?????