It has unfortunately come to my attention that I have been undercharging for international shipping. It seems any order that contains Apawthecaria + any other zine is pushed out of the large letter category and into the small parcel category so while I've been charging £11 for shipping to the US, I've been paying £21 to ship those orders.
I'm going to try find a solution to this but for the meantime, I've had to increase my prices where appropriate. Sorry!