There is a lot of background to this so please bear with me.
I had a friend who I met 15yrs ago at varsity. Lets call her Z. I met her through a guy I dated at varsity (J). J always held a candle for Z. She is very charming but also manipulative. Makes you feel like the only person in the room one minute, and then you are invisible the next. J and I got engaged, but him being constantly hung up on Z led to me breaking up the engagement. Z and I became close friends. She was bridesmaid at my wedding. Later on we had a very unfortunate thing in common: infertility. We both had multiple IVFs. I had 4, the 1st one let to twins who were born very prematurely and the one baby passed away. After that I had 3 more IVFs, all failed. I was advised that the only hope would be donor eggs. Started with the process, but miraculously fell pregnant naturally during the donor egg IVF process. Z had many more IVFs (8 or 10, they are rich) but so far couldn't conceive a 2nd child. Her first-born goes to the same nursery as my surviving twin girl and they are now best of friends.
On to the other side of my dramas: I have a very difficult dad. He got remarried after divorcing my mother. I gained a step-sister and -brother who were given everything that we were denied when we were young (a happy home, fun, love.. not talking about material things). But I worked hard at accepting them and building a bond with the step family. I came to adore them all, in particular my stepsister who is 10yrs younger than me. But then my dad's true colours shone through and they got divorce. This happened at the same time as I was going through the donor IVF thing. My stepmom asked me at the time to talk to my dad, but wasn't specific about why. I didn't realise it was so serious and postponed it to focus on my own problems. Apparently my dad was so terrible to them that my stepsis now need medication and therapy and get nightmares. I'm not too surprised, I grew up with the man (it's all emotional, not physical abuse). The difference is that she had it for 10yrs, I had it for 20. And I can't just get away from him like she did.
So then there I was pregnant with my miracle baby while the divorce was happening.. and Z became very distant. I asked to meet up for coffee to talk about why she was becoming so distant. So we met up and she laid into me. She was angry because I talked about struggling with infertility but she had so many more IVFs than me, so I dare not speak about it. I also still talk about my late son and become sad about it and she is tired of hearing about it. And every time she contacts me I tell her that I'm in hospital or having contraction (2nd pregnancy was very high risk). Basically she assassinated every aspect of my character, and just as she had me in tears when she started on my late son, she got up and walk out to the toilet, leaving me there alone and crying, then came back to continue the attack. At the end of that meet-up we decided that we will redefine our friendship, no more talking about infertility. I wasn't 100% happy though. Then things got worse because Z and my stepsis became very close. Stepsis arranged Z's daughter's birthday party. I asked her for help with my girls' parties but she never did help. Stepsis babysat for Z. I asked for help with my oldest while my youngest was a difficult colic baby. She didn't help. Stepsis stopped contacting me. Z barely ever contacted me and I had to see the posts on Facebook of Z and stepsis being best of buddies with me completely pushed out. So I did something that I guess was wrong. I was hurt and emotional and send a nasty message to Z that she hurt me, she is like a parasite (ugly, I know), she used my stepsis to hurt me further and I didn't want to be friends with her anymore. And I uninvited her to miracle baby's Christening (also ugly I know). That was over a year ago. I never discussed with stepsis what happened with Z. Don't know if Z told her version to stepsis. I never hear from stepsis anymore. Z's daughter and my oldest daughter are still good friends. They've been to each other's birthday parties. Z gave me a hug at my daughter's party. I invited her daughter over to play at our place. Z came along and we had a good long, civilized catch-up. I thought we made peace, but I was OK with us not being friends again. Then last weekend I took my daughters to a kids venue which is also a party venue. We ran into Z and her daughter who were attending a party. The girls wanted to play, but Z didn't even make eye contact with me. She just sent a friend over to basically chase us away. And I still never hear from my stepsis.
I feel incredibly hurt. I know I had a part in it when I lost my cool with Z. But I feel betrayed by my stepsis. Like I was traded in for Z and being punished for my dad's sins (stepbrother also not talking to me, but I'm still close to stepmom). And I feel that Z used my stepsis to hurt me deliberately.
Am I being over-sensitive/unreasonable? How do I let go of it? It's been a year since things fell apart, but I'm still crying my eyes out.