what is my facebook username?

[Austine Osaro]

forgotten my Facebook username

[Unique]

are you able to access to access your account..??
if yes.,
log in to your profile.,have a look at he URL (address bar)
The extra thing after https://www.facebook.com is your username..
example https://www.facebook.com/Indian.Army.,
in this "Indian Army" is the username.,

[Daniel]

Do you Mean your Email Address ? If So We Cant Tell you That Only you Would Know if you Dont Know it you Can Not Get Back Into your Account

if you Mean Username as In your Profile Username It Should Tell you That When you Go to your Profile on the URL Box