I had to stop playing about 2 minutes in and run out to the store to get some motion sickness medicine because I was already getting sick. I've never been hit this hard by motion sickness before. The only other games that have really affected me were Dead Island and Fallout 4, both because of awful frame rates/frame pacing, and for both of those it was a few hours before I started feeling ill.
I'm waiting for the medicine to kick in before I start playing again. I hope, as Brazil said, it gets better after Aloy grows up; otherwise, I think I'll be returning this game and waiting to try my luck again during a sale.
The worst thing about motion sickness for me is that it doesn't go away when I stop playing. Once it starts I'm stuck feeling sick for hours.
I don't know if the motion blur and slow camera speed are contributing to it, but they definitely aren't helping.