Have you checked with Rodney whyte or one of other drug info centres if there are alternative meds?
https://www.breastfeeding.asn.au/bre...urces/medicine

You might find that you still have milk after a week. Boobs that reach toddler feeding age can often be quite adaptable, and will bounce back. Going cold turkey you might find you need to express for comfort too. or you might find that this is a good opportunity to wean, and not offer again.

hope you feel better soon.