Don't forget, how you "act" in the world is behavior, not "you". You are only inside and You are the only one who can "know" You. However, it's easy to forget/lose/focus somewhere else (outside or on what others say) and feel you don't know who You are.

My T was helpful telling Me to "check your heart" and giving Me space and time to do that when she'd ask a question of Me. It takes time though to discover and hear your inner voice. But realizing that no one "outside" you can truly tell you what you think and feel, only what they perceive watching and listening to you is a great first step, lets you know that you're the expert on You and that you're in there. . . somewhere :-)

Putting it in the words of your title, An onion is still an "Onion" with no center!