Hello

Don't worry  about it. Firstly go the registered email. When you are registering for the same ,they usually send you mail which contains your login id /username .. so you can get that from your registered email  id. Pls check spam folder also some time it is received in spam folder also.

Or you can go for forgot login id /username ,on that government website, so that they ask few question and then you can get the access to your account.

Good Luck.