HELP!

I recently created a new yahoo account. I was called into work and didn't bother to write the information down. I've tried every possible way to retrieve my password and id. I'd create a new account, the only problem is I had written a very important letter to someone the sameday I created the account, and I need to retrieve that letter. Is there any possible way to retrieve the forgotten information?

I'll take anything,
much worried,

Deanna