BRA SIZING HELP

everywhere I go there is a different answer I am a 28 under bust and 33 bust so far I asked Victoria secret 3 times and they all said I’m a 34B, 30D, or 33A. I currently wear a 34B but i am thinking it’s a little too snug in the boobs I have to loosen my straps for it to sit right and make the band tight as possible, but all my bras are too old to give a accurate description.. and every online site calculator says I’m a 30DD 🤦‍♀️ so I’m very confused and need some help thank you all!