Went from 475cc to 1000cc 2 days post-op! What should I do?

That is a very large implant.  They will likely soften over time, but they will never be as soft as your 475cc implants were.  As long as you have the look you were going for, that's where you should put your focus.  Worst case scenario, you can always go a bit smaller.  Good luck!

Not sure 1000cc implants will ever look or feel super natural...as the swelling resolves, the breasts should soften. Hope this helps!

Larger breast implants do tend to feel firm;  however, over time the breasts do tend to "soften" to a great degree.  Given your concerns, I would suggest that you communicate directly with your plastic surgeon; keep in mind that no two patients are identical (what I recommend to you may be different than what I would recommend to a different patient with similar concerns).  Best wishes.