Thank you for contacting JustAnswer, I will assist you with your question.
Have you tried the forgot password? Since you don't remember your username, you can enter in the email you used to register your account.
I have no way of finding out the username without having the registered email you. If you cannot remember and its a fairly new account. I would just recommend starting from stratch and use a email where if you forget your password XXXXX can retrieve it from with the registered email.