Your water retention will go, I imagine your surgery was double the length of a normal augmentation because of the uplift so imagine you almost have double the anaesthetic to get rid of too!
I don’t think you look small, I had 275 also and the 32DD wireless/seam free bras I got to wear for post op are on the tight side so I haven’t been able to wear them! Give them time and hopefully you will love them and it will all be worth it!