<human>: I've been close to these 6 dudes for about 3 years now. We were in the same class, would constantly make plans, hang out. I was always invited.  

 However, from last year to now, we got divided into different classes at school. 2 of them stayed with me, one went to another school, one stayed in ninth grade and 2 others went to another class. Since then, they've made new friends, I've made new friends, but when they would make plans that involved the group, they didn't invite me.  

1 of them has been particularly cold to me sometimes, alternating between literally pretending I don't exist and hanging out with me normally. I've been really bothered, because recently, one of them (the oldest) had his birthday, and I saw pictures on Snapchat of all of them together, excluding me. I didn't even know that he was going to throw a party. Today, they all went to a local pizza place.  

They still talk to me, I still make them laugh, and I can't even think about something I did having upset them, but they simply don't invite me to stuff. I'm confused and I have no idea what to think about them or this situation.

Can you give me the gist of the text in a nutshell?
<bot>: My 7 friends of 3 years no longer invite me to plans involving the whole group, but still talk to me. One of them had a birthday party and I was the only one not invited of us.