I still would... I mean of course you would have worn it thats how you would have realised that it did not fit properly..I see it that you went in to get professionally fitted and they ended up selling you a bra that was the incorrest size and believe me i have worn a bra when i was breast feeding that had half of one boob sticking out and i ended up with mastitis soooo not good... If you don't want to take it back you can always go there and get refitted and tell them that you were fitted wrongly before