Bra size

I have had a wavering bra size for about a year and a half. I was told at PINK that I was a 34B in last December. In July, I was told I was a 34A. The same day, I was told I was a 30 4B and then a 32C. I went to PINK yesterday thinking that I was a a 32C (keep in mind that I owned two or three different bra sizes). The woman there then told me that I was a 32D. Despite being excited by this news, I was a bit surprised and was also confused. I didn’t think there was anyway I could possibly be a 32D. They don’t seem that big. Does anyone have any advice as to how I should figure out what size I actually am? This has been a big problem for me. Please help.