I think I know where you're going with this. I could be wrong with this, but it's quite possible that you've been told that Mary is not a "Mother" in the sense that she is the origin of the Godhead. The apostolic churches have never taught that. She is the Mother of the Second Person, who, as the Athanasian Creed states (and as I repeated in my last post), "although He be God and Man; yet He is not two, but one Christ. One, not by conversion of the Godhead into flesh; but by assumption of the Manhood into God. One altogether, not by confusion of substance; but by unity of person."
I think you do agree with the statement: "Many people use the word God interchangeably for the word Godhead."
Did I understand you correctly?
If so, then you can see that it is more CLEAR to be precise when talking about whom Mary is the mother of. Mary is the mother of Jesus, the incarnate 2d person of the Godhead.
Do you consider this position to be heretical?