I don't really know where to start explaining this, but I have such strong negative feelings towards someone, and I recognise that I need to let it go. This may be a bit long, so I apologise in advance, although it will probably be quite cathartic to get it out.
DD had a friend at school who she had been 'BFFs' with since Year 1. I didn't necessarily encourage it, but they were into the same things and everything seemed great. I became friendly with the BFF's parents, and I would see them in group situations with other parents who were friends of ours, or on our own - I would sometimes go out walking with the Mum in an effort to keep fit.
Last year I noticed that we had been seeing a lot less of the BFF, and the Mum hadn't responded to a few of my texts suggesting going for a walk, however that in itself wasn't that unusual as she was very unreliable. At Christmas last year my DD, then 9, broke down in tears and I discovered that the BFF had been bullying my DD for months. Lots of moodiness, yelling at DD for no reason, deliberately excluding her from activities and making a huge point of favouring others. I found a few diary entries my DD had written and I felt absolutely dreadful for her. I spoke to her teacher about it, and she was sympathetic, but her main advice was just to stick to the other friends who DD had (and thankfully she had quite a few other friends). I had no contact with the Mum, other than a superficial hello at the gates, which to be honest I was fine with.
So in May this year the Mum contacted me and asked me out for coffee. I was surprised, but agreed, although when we met it was absolutely surreal. The Mum had said she would pick me up - she was over an hour late. When she was parking the car her mobile rang, and she asked if I would answer it, and said 'Just say you are my PA'. I was 
and of course didn't say that. During coffee she was really negative about anything I said, for example, we were in the process of buying a house, and she was very derogatory about it. She then proceeded to make several longwinded calls to her DH and her other DD whilst we were having coffee, which I thought was really rude, but for the sake of niceties I didn't make a big deal over. On the way back from coffee, rather than dropping me off directly, she then made three stops at different properties that she is developing / renting out. She made a massive point of giving the plasterers a complete bollocking in front of me, stopped to get a tenant to sign some form, and drove me to yet another property. Throughout all of this I was saying things like 'I really must get back, I have lots to do' (and I did - I only get one day off during the week, and the time is precious to me). When we finally pulled up outside my house, the Mum then turned to me and said 'I know what happened between the girls' I was 'oh?' and the Mum then started to do a complete character assassination of my DD and told me she had brought it all on herself. There were plenty of things I could have said about her DD, but I was so shocked by what I was hearing, and I didn't want to make it into a tit for tat argument, so just made my excuses and left. I feel as if I was really spineless in not pulling her up on her behaviour or what she was saying.
I felt absolutely awful about the whole encounter, and the feeling I had was that the Mum had made a point of trying to demean me by being rude to me, wasting my time and trying to big herself up by making out she was some sort of property magnate. I spoke to a close friend about it, and she was wonderfully to the point and said that she always knew the Mum was a complete fucking oddball. My DH said he had always thought she was manipulative and divisive, and when I think back on things, she was always someone who had a horrible word to say about everyone, and thrived on nasty gossip.
The former BFF continued her bullying campaign during the summer (at summer camp) and into this term. I spoke to DD's current teacher who has been amazing and has dealt with the issue - has placed the former BFF on probation because of it. But this has also brought things to a head with the Mum. I'm not sure what, if anything has been said by the school, but I am quite sure the former BFF will have cast herself as the victim and gone home with a tale of woe. A few weeks ago the Mum had a go at me at the school gate, and made reference to personal information that she could only have got from a mutual friend. Although I was calm but assertive in the face of it, I now feel sick every time I pick up DD. The Mum is very overbearing, and a lot of people think she is quite funny as a result of it, but having seen what she has been like, especially in condoning her daughter's bullying behaviour, all I see is a manipulative bully.
There are mutual friends, and I have a feeling the Mum has been bad-mouthing me, and although I would love to say something to the mutual friends, even if just to say 'look, things aren't great, I'd be grateful if you didn't discuss me with X', something holds me back. The other thing that really sticks in my throat is that now the Mum is really pally with other parents who I know she has spent the last 6 years making bitchy comments about them at every opportunity.
I know this is trifling in the scheme of things. I have been off work for a while due to illness and I recognise that in the absence of work stimulating my mind, this is perhaps why this is annoying me so much. (The good news is that I go back to work tomorrow!)
So, if you have managed to make it to the end of this - have you any words of wisdom as to how I can teach myself not to give a shit about it? DD is in Year 6, and I am hoping against hope that the other child won't go to the same school for year 7. I am quite literally counting down the weeks to the end of the school year so that I don't have to have anything to do with this woman.