Hi, I’m currently wearing a 30e or 28f. I have noticed these are a bit big in the cup so remeasured myself using the boob or bust calculator. This has said I should try a 28dd or 28e as I fall in between the two sizes. My concern is that a 28f digs in badly and is very uncomfortable so I have had to start wearing one of those back extender things with it to make it comfortable. Surely a 28dd or e would be just as painful? Can anyone advise what size might be best to try. According to the calculator my ideal sizes are 26f or ff but it has recommended the 28 back due to 26 not being readily available.