Constant friend betrayal

I'm in my third year of university and I feel so incredibly alone. When I look around the cafeteria and see groups of friends laughing and truly connecting, it physically hurts. It feels like I'm stuck on the outside looking in, and I just don't understand why.

My friend struggles started in high school. My ex best friend suddenly removed me from everything social media, phone number, everything. I tried reaching out, asking what happened, but she read my messages and never replied. To this day, 5 years later, I still wonder why.

The person I vented to about that heartbreak, my second ex-best friend, did the exact same thing to me just two weeks later! They have nothing to do with each other and don't even know each other, which makes it even more confusing. I was so heartbroken that I never even called to ask why. I just thought I would get over it

My high school friend group was also complicated. A big drama happened with one of my closest friends, and she tried to ruin my reputation, She failed, but eventually came back asking for forgiveness. I gave in, but nothing was ever the same. We barely talk now

I have three other friends I consider "online friends" now because it's so hard to see them. I only meet one of them at the university gym maybe twice a month. It feels like I'm stuck in limbo

Just last week I saw a group of girls in the cafeteria talking and laughing, and it was so hard to watch One of them was an old classmate I still like, and the other was a girl from the gym who had come up to me, hugged me, and said hi. It just makes me feel so invisible and alone when I see others sharing the kind of connection I so desperately miss.

I miss having friends to exchange thoughts with, to laugh out loud with, and never having to think twice before saying anything. How do you heal from so much betrayal? And how do you even begin to build new, healthy friendships when it feels so hard to trust? I'm just looking for some advice or hope has anyone else felt this way?