So I was in this amazing friend group, we've known each other for a really long time and we've been friends since primary school (since we were 9-10 years old). When we went to secondary school (ages 13-16), we all got in the same class and our friendship grew even stronger. We had a lot of sleepovers and we hung out at school a lot, just like any group of friends at that age. 

One of the friends in that group, I'll call her Amy, confessed that she liked me. I have a damaged history with things like love and crushes, and I was young and stupid so I figured that it was going to be awkward and destroy our friendship anyway, so might as well just go out with her and delay the awkwardness. We started going out and I think I grew to like her romantically as the relationship progressed. It was a very toxic relationship and I didn't really realise how bad it was until recently since I've started to work it through in my head. We broke up several times during the relationship, it was always her idea, but we got always back together, her ideas again. This on-and-off thing went for around a year, until I broke up with her and she started hating me for it. Like, really hating me. 

I didn't know what to do with our friend group, we tried to act as if nothing had happened but it was extremely uncomfortable. I'm not a big fan of confrontation, so I thought to myself that it'll be only one more year until we'll all go to high schools (ages 16-19) and most of us will go to different schools. While we were trying to act like nothing had happened, we had one sleepover that I was looking forward to, thinking it would be as fun as it used to. I ended up having a panic attack in front of my friends and none of them helped me at all. One of the worst experiences in my life. That's when I realised that we couldn't pretend nothing happened and I started distancing myself from the group. I still had to hang out with them at school, and I really hated it. It took a toll on my mental health. Even with all the bad things that had happened during and after the relationship with Amy, I try to not blame her or think of her negatively. The situation is so complicated that I don't know what's the right thing to do. I don't know whether I'm allowed to blame her and hold her accountable for the things that happened during the relationship, so I'm trying to be kind regardless of everything, because being kind to everyone is my core value. 

We got to high schools and I was finally able to get a fresh start in a new school and get a new friend group. I had some difficulties there as well, and right now I consider two people out of my old friend group my best friends. I still see them occasionally, but only one on one. I thought that the whole friend group had just grown apart. 

Until today. It's been a really rough summer for me, and even though I have progressed a lot with my mental wellbeing, it's like the universe decided to test how much bad things I can take before I completely fall apart. Today has been one of those days where I haven't been able to get out of bed before three in the afternoon. I tried to turn the day around by going for a bike ride, but when I got home, one of my friends from the old friend group had posted on their social media account about them hanging out with everyone from the old friend group except for me. I broke down crying and I really don't know how I can recover from this. 
What do you think? How can I deal with this? I'm supposed to meet the friends I still keep in contact with in a few days, how can I face them and not cry my eyes put in front of them? 

Note: I'm not sure if this is a good story for r/depression, I've only used reddit once or twice before and this was the most accurate community since I have been struggling with depression for quite a while and this event affects my mental health negatively. If you know of a better community, however, I'll gladly move this post there. 
Also, please excuse any errors in regards to my writing, English isn't my first language!