I’ve not read all previous replies so apologies if I’m repeating what others have said.
It wasn’t your wedding day, it would have been but as it never happened it wasn’t, that would be like saying it’s your wedding anniversary when it isn’t.
Your best friend wasn’t your bridesmaid, she would have been but as it never happened she is just your friend.
They are a group of friends on holiday, not the wedding party, where her boyfriend has proposed.
You would have been upset however you found out so rather than you hearing it off someone else she’s had the decency to phone & tell you. Rather than being pleased for her you have pretty much cut her off & ruined what should have been a happy moment for her.
Its been 4 months since you had a lucky escape, he it been in the days following you having to cancel your wedding then yes, a bit insensitive, but 4 months later?
It seems very dramatic on your part like you are trying to make it all about you?