Did I over react

Nicole • 18 and going to be in a long distance relationship in three months 😬
I've been having some drama with my boyfriend. Started with my graduation he decided to spend time with his friends that day saying it was pre planned a week in advance and my party was the next day I was very mad and hurt. Then his friend a girl got dumped and they where going to hang out because she "needed help with her mental state. Then that day she winds up in the hospital saying due to the breakup she can't even keep water down. And posts it in a group chat claiming she didn't mean for him to see it but he was in it. I recognized this behavior pattern due to an abusive relationship from my past he went over anyways siding with her over me. I ended up being right she called him and lied to get him to see her. But he said its ok to think the worst in people due to my past. Who was wrong or wss it both.  He said I've caused drama recently.