It is very possible that you have written down your public key instead of your password. Your public key is NOT your password.
If you created a cloud wallet, your password is an auto-generated 45 character password shown when you created your account. That is the only time you will be able to see and record your password.
If you created a local wallet, you are given the opportunity to create your own password but you must still record a backup of you keys, brainkey, username and password. Should you need to restore your local wallet you will need those backups. Without them no one will have access to your local wallet account.