For you to get back to your Old Level, you have to remember your Original E-mail Address or your User ID Number. If you don't remember your Password, you can have it Reset by providing your Original E-mail Address that you've used when you first registered for the game. On your first comment here you said your Username was "Serra", do you remember your E-mail Address associated with that Username? Your E-mail Address or your User ID Number identifies you as the owner of the Account and without any of them, it will be impossible to find your account from approximately over 100 Million Users.
When you create a New Account with a New E-mail Address, that will create a New User ID which will NOT be associated with your Old Account.
To avoid this from happening to you again, I would suggest that you keep record of your E-mail Address and your User ID on file that you can go back to when you can't recall them. I understand that with evolving technology plus all the things happening in our daily lives, it is difficult to remember everything.