I can't sew but I bought some bralettes that fit my big chest about two years ago and have worn an underwired bra maybe twice since (when I had to dress up around my family). It's been life-changing. My vision of myself is also flat-chested and in a funny way, while I'm still of course anything but, the bralettes help with the disjunction between my brain and reality because I hardly ever spare a thought for my chest all day when I'm wearing one; they're comfortable and unobtrusive in a way no other bra has ever been for me, so they feel invisible.