Am I an impostor?

Sometimes I feel like I am an impostor. I pretend very well to be a wife and mother of five. Back when I was trying to decide whether or not to major in Theater I realized one day that I have been acting all my life - or at least most of my life. I chose my life but really I have not been raised for such a life. What I mean is that I am acting contrary to my conditioning. I didn't like my conditioning so I chose differently. I suppose there is a bit of nobility in that. But sometimes, there are moments, when I feel like I am an impostor. I get these feelings when something reminds me of the dark times in my childhood. I don't want to remember them. But they come up. Right now I am studying substance abuse. Maybe it is not a good idea. When I read about those who are prone to abuse I see that I fit those profiles. I could have been some kind of substance abuser. But I had absolutely no desire. I wanted a better life. I have lived a clean life but there is dirt inside of me that I can't seem to wash off no matter how good my life is. Maybe I should reconsider being a therapist. Maybe I need to do something else, something that won't remind me of my past suffering.