Ah @"Kiwi Angel" I want to scream for you - it sounds like you've done a lot of that and more today. I stew and stew on things like this and re-live the anger every time I think about it so by giving you my 2cents worth, I'm going to be one of those really annoying 'do as I say, not as I do' people, it's always so much easier to give advice than to take it yourself, right?
Still, the one thing I want to add is that this is HER problem and she will be the ultimate loser in the end because you will now distance yourself from her and she won't have any more 'news' to spread in the future.
I always say to my kids when they come home upset or angry that no-one can has control over your emotions apart from you. Only you can dictate how you feel about something. People can do their very best to get you angry or upset - it never ceases to astound me that there are people who do everything they can to upset someone (How can that be fulfilling? Knowing that you have intentionally caused someone grief?) but ultimately it's up to you whether or not you let them. It can be SO HARD to keep control when someone has betrayed you - and if you can do that in public (then crumble in private) then you have WON and they have LOST because as far as they are concerned, they have NOT succeeded. As I said, this is way, way easier in theory than in practice but it sounds like you've totally got this now and have come out stronger for the experience. Go you! xxx