If I am not authentic then I am nothing.

There is no such thing as an inauthentic self. Perhaps if you were a forgery or a replicant. But then you are not yourself either, well you would be yourself but that self wouldn't be you... uuh , or rather, them. What I mean to say is there is no way to not be yourself. Like it or not, what you see is what you get, the irritations, the angers, the depressions and the fears. We try to distance ourselves from all that we don't like to see in ourselves, but if we do this by distancing ourselves from ourselves then we have progressed nowhere.  What are you talking about Ryan, you say, of course we are ourselves. So I keep talking 

We like to have reasons, excuses for our shortcomings, we excuse our physical natures because we have a genetic predisposition, we excuse our societal mishaps because of our socialization and the way we were raised, we may even try to excuse ourselves of inexcusable actions because of an uncontrollable addiction. So is this a legitimate claim, that because we didn't have a say or part in our biology and early socialization that this self has been inflicted upon us and is not our fault, not our true self? Are we seeing ourselves with a pre-birth existence and that we now act in a way untrue to this previous self, but this current dual nature would still be combined to make one oneself. Harking to the past for accurate measures on self is no answer. Or do we claim that being something different from what we imagine or hope causes this inauthentic state? But if this were the case would there ever be authenticity? Who doesn't see themselves different from reality? And what of competing views and desires. Harry Frankfurt while discussing free will and determinism came up with an idea that I rather like, it splits desires into first and second order desires. And we often have competing first order desires, such as a desire to eat healthy and a desire to eat ice-cream.   And we then have a second order desire based on the first such that we have a desire that our desire to eat healthy will be effective. We can also have a second order desire to have a first order desire, such as a desire to want to exercise regularly even though we don't have a first order desire to exercise regularly.  So our desires seem to fall short in a measure of true self. Frankfurt also states that moral responsibility does not require that an agent have the freedom to choose otherwise. Or rather that we are responsible for our actions regardless of their source and influences.

There is something to the idea of improper assumptions on the part of another. Where you are not what the other thinks you are. But this is inevitable, you can never guarantee that others see you as you wish to be seen or as you truly are. You are the one defining yourself to the world around you by the descriptors which you attach to yourself. and actions which others see. I fully respect another's desire of self definition but shouting inauthenticity is a weak mans effort to excuse themselves, to distance themselves from themselves.  We are who we are and we should not feel the need to excuse ourselves to others, but we will need to take responsibility for that which has been dealt to us.