First of all: Do not panic. This is not tragic at all, anyone has been in this situation. You can choose between two possible ways to get your password (and of course your account) back.
I still know my registration password!
With this option, you can reset your password. It will be the same like when you created your account.
I need a new password!
If you do not know the password you chose at your registeration, then you can request a new one.