Well, then no one person can really call themselves Polish. Not even those who inhabit Poland, in that case. But as my Parents and Grandparents have always told me to be proud to be Polish I cannot let them down, it would be hard to, I love the Polish culture and i'm proud I am Polish.
Exactly. Very few Poles can trace a clear unbroken linage of Poles back to the founding of the Polish state, and indeed, the variety of surnames in Poland prove this.
As for being proud to be Polish, what have you done for Poland? Being proud of a nationality is rather silly unless you contribute to it, in my opinion.
From what you say, localities are much more important, so it would be crucial to find out what part of Poland Doberski originates.
Seems to be Pila, but I suspect the name has been changed somewhere along the line, possibly upon emigration to the US.