Right, but in this case, I returned to Canada with my mother to live. I dont see why Canada wouldn’t recognize me as a “full” Canadian.
Had my mother only given birth to me in the US so SHE could obtain US Citizenship through me... I would see your point. But that is not the case.
Were the associated costs of your US delivery paid for by provincial healthcare under some agreement that directs Canadian residents to the nearest hospital even if it is in the US or did your mother just decide to go there on her own? if it is the former then maybe you have some compassionate case to make that you are not really a citizen by descent, but that's a long shot.
BTW, you are recognized as "fully Canadian." There is no second class Canadian citizenship (as there was when the Conservatives' citizenship stripping law was in effect) anymore. Its just that your kids aren't Canadian. Its a property (or lack thereof) that pertains to your children, not you. You can sponsor your children to immigrate to Canada and once they land apply for them to become naturalized citizens.