That's right. It's a big lot of files. I'd be concerned about your D/L speed. Someone might be able to confirm or maybe a Dev could have some input; but I think you can pause the download and shut down the launch program without affecting the install (?) You could have a problem with your connection and restarting your computer might put it right again. Unless your download speed is always that slow.... Another helpful pointer: you haven't reached your service providers download limit and being throttled by them in anyway?
I'm no professional so please don't blame me if this doesn't work.
Hope you get your game installed soon and hope you enjoy your game!!!