When you say you don't remember your yahoo email, you mean you don't remember your email address? If that is the case, ask someone you emailed recently. Then just contact yahoo from the homepage with the "I forgot my password" link. (not sure where it is, but most email systems have one if yu search for it!). Does that help?

Best bet is to make a TXT file with your passwords on it and hide it somewhere, just don't forget where you hid it.