So you only calm down once you see all other friends are not going too!
So, a women who you think is close enough to you for you to ask to be a bridesmaid, you did not believe when she said they were only having a small family wedding, you had to wait for the "proof". I only hope you have not let this strop, and that is what it is, be known by your friend.
When you say your fiancée might not take it well, and not even invite them to the reception, is that to say she is now no longer even a bridesmaid!?
For what it is worth, I was not bridesmaid for either of my bridesmaids, I got married first, then one got married a few months later, and did not tell anyone, was just the two of them at a registers office with random people for witnesses, and the other one, she got married abroad, and had about 7 people there (pretty much parents and siblings and one friend), we were invited, but we would never have really been able to afford it, it was not the place we would have wanted to spend our first holiday as a family (we had 16 month old by this time) as it was a very adult place, and I ended up being due with second dc the same day anyway. They are still two of my closest friends, and I was never anything but happy for them. I was my sisters bridesmaid years before when I was 15, she was not mine, although her daughter was one of my flower girls.