Not necessarily a bad person, it would take a lot more then stealing a facebook password to be considered a "bad person" in my eyes. However it really depends on your overall ethical views on what you think is ok/not ok to do.
BUT
Depending on where you are from, you may have just broken the law and criminal charges could be placed if you are reported to the police.
Why don't you answer your own question. Obviously you feel bad enough about it to ask other people. Why don't you develop your own moral compass and realize you don't feel comfortable with it, therefore it's wrong. Besides you stole her password, and we all know stealing is wrong.
Though bit torrenting stuff is a little hazy in the copyright laws.