Digitial pre-order (54 GB) not letting me play

I downloaded the digital pre order of Halo 5 a few days ago, and when I went to play it after 12am my time it took my to the microsoft store and prompted me to install the game. As I said before, I completely installed the pre order edition so I’m not sure if it’s re-installing the game or if it’s just downloading an update. With my bandwidth cap I can’t afford to re-download the entire game and honestly I’m just not sure what’s going on as the game is in “queued” but is clearly downloading something as my bandwidth usage is going up. If someone could give me a heads up as to what’s happening, that would be appreciated.