There is nothing you can do. An account key could have been sent to an alternate email but you did not register an alternate email when you had access to your account. You should have taken that security precaution but you did not.
There is other way to recover your account you need the account key.
Unfortunately, if, when you created the account, you have not registered an alternate recovery email address to which you have access to receive a reset code, you cannot prove that you are the account's legitimate owner. Hence account recovery is absolutely impossible and there is no way around it.