Re: pump weaning a little early
Since it's 3 weeks away I would, Add in extra sessions including the next 3 weekends if possible. Since you are literally talking about a matter of weeks perhaps 3 weeks can be where you "begin" your pump weaning. Since cold turkey is never really a viable option. I would also look into a car adapter. Perhaps you could move pumping while driving? On the way to and from? If you do this in conjunction with a freezer stash over the next 3 weeks I am optimistic you could make it the 5 weeks to the year point with no formula!
Re: pump weaning a little early
I would not supplement either...I'd probably encourage reverse cycling.