To be fair to op there have been times when I've bitched about friends and their kids - sometimes with justified provocation sometimes when I've been unreasonable. Because I am a human person that sometimes has a bad day. I am fully expecting that the same happens about me and mine - because my friends are human too.
I feel it unreasonable to expect your friends and loved ones wont do things that rub you up the wrong way occasionally. BUT if you have to let off some steam to prevent yourself from brooding on it choose those listening ears very carefully. It's not ok to air those feelings in a public arena - off having a gossip in the kitchen at toddler group for eg.
OP is feeling terrible. ex friends kids may have been awful? Hitting, biting, bullying, obnoxious - whatever. Maybe not - we don't have all the info.
As mothers some of us are inclined to get precious about our special, special snowflakes and refuse to hear even the mildest of criticisms of their behaviour. I'm sure there is at least one example you all know- and the kid(s) are usually the bullies or bad boys of the playground. Mine are not the angelic little cherubs I like to think they are, they're learning to be people still, but I fell they're good 90% of the time. They are certainly kind and always try to do the right thing - but some mums don't parent like me and things I'm fine with might be seen as really rude by others and vice versa.
OP - resentment is like drinking poison and expecting the other person to die - and you 'ain't keeled over yet. You are apologetic and feel ashamed of the situation, she doesn't want to know and is behaving really childishly (which is what lead me to belive she has snowflakes). You have approached to make amends and rather than saying 1) let's move on but... or 2) I'm sorry but I can't move on we're parting ways and civility only now she is mucking around with tactics most school girls are embarrassed by at 14. You can communicate in writing (text, msn, fb etc) and let her think when she isn't on the spot and if she's still not interested just go ahead with damage limitation with any friends that mention it/are affected by conflictng friendships with both of you - own up, take responsibility and explain your amends. Don't feel bad about everything if she has equally bad behaviour to reconcile! Your good friends will know your good character and accept your explaination - not going over old ground so they can get goss and pick sides! Just the ending and then - move on, older and wiser as they say. I also want to give you a friendly slap for getting all 'everybody hates me, I'm going down the garden to eat worms' anyone that 'hates you' then were they worth spending the energy on? Seriously the more you get exposed to other mothers at the school gates etc the more you feel sad for all the women that never grew up and left high school - their lives must be sad if they need the drama or they are just immature and will soon be tired of by others if they deal with everythig the same way they did at 13. Mature adults don't act like that and I don't want another teenager to deal with, it was pathetic enough at the time! Chin up chick xx