I had been warning you that you were skating very close to adopting Nestorius's position back when you were advocating 'Mother of Christ' instead of 'Mother of God'. That's part of why I was insisting you find and read the acta of the Third Ecumenical Council. The others noticed, too. (I like to joke that we Orthodox are issued an 'I Spy Book of Heresies' at chrismation, so we can recognize them easily even in modern guises.)
While you're at it, the acta of the Fifth,would be good to read, too, since that council formalized as a doctrine the long tradition that Mary remained a virgin, 'before, during and after' giving birth to Our Lord, God and Saviour Jesus Christ, as well as condemning Theodore of Mopsuestia (Nestorius' mentor), and certain writings of Theodoret against Cyril of Alexandria and a letter of Ibas of Edessa to Maris (though not condemning Theodoret or Ibas themselves for heresy.
I read what the objection to Nestorius's view was, and it does not apply to me. Jesus was indeed Christ. He was the only person of the Trinity that was Christ. Therefore, Mother of Christ sounded less confusing to me than Mother of God (which includes all 3 persons of the trinity theorhetically- but the way the council defined it, I understand does not). Jesus was not a "God-bearer" as I believe Nestorius believed. He was God.
Mary's child was God and Human. But she didn't give him His divinity (which I understand is not the claim) and He preceded her (eternally). Beyond that, I really do not wish to explain it again other than to say, Jesus was by nature fully God and fully Man in Union in one person. That is not Nestorianism.