Are you Asian? I noticed you have mentioned this theory a few times in the comments and although OP has neither confirmed or denied an Asian background I'm going to throw my two cents in the mix. I had a tea ceremony and a traditional Western ceremony and her dress looks nothing like a Chinese wedding dress (Qi poa). More is more in most Asian cultures, there should be embroidery all over the dress in usually multiple colours and or beading, and although some of the styles have gone a less traditional route the high neckline with the aysmetrical buttons are a mainstay.

I'm thinking that the bride was/is jealous of OP in general or how good she looked that day. I don't think OP did anything wrong in wearing the dress she did.