Your probably just getting used to the size now, but I wouldn’t get measured yet it’s only 2 weeks to wait and alot can change in 2 weeks.
I had 415 unders and I’m a E/F cup so you’ll probably be about the same. Be patient, you’ll soon be shopping for new bra’s. When I got measured in Ann Summers the girl said ” I hope you don’t mind me saying but you’ve got a cracking pair ” lol Xx