Am I overreacting?

Me and my boyfriend went on a trip for his brothers wedding I was not part of it so I was feeling left out and I also did not know anybody, they have a family friend that they have known for 10+ years I was mostly left alone since I was not part of the wedding I only got to talk to my bf till after the ceremony and even then we hardly talked because he spent most time with the family friend, they talked a lot and once in a while I will glance at him and I will see him looking at her then she would grab him by his arm and also he was sharing drinks with her which it’s a big thing because he’s a germaphobe and he will absolutely not share drinks with anyone except me I did ask about that and he said if he had a couple of drinks he doesn’t really care but if he was sober he would have not done that. After the ceremony we went to our hotels to get ready for the after party and of course once we were ready my bf wanted to wait for her we even went to his brothers hotel so we can all go together he did leave the hotel room to go get them (her and her sister) because he didn’t want them to get lost and that’s when his brother told me “I don’t know why he did that If she knows where it’s at” on our way to the after party I was walking alone while he was in the back talking to the friend and in the bar I would see him looking at her dancing. I didn’t bring this up to him cause she’s a family friend and I didn’t want to be that crazy girlfriend but now it’s really getting to me and I don’t know if I’m overreacting especially since I was not part of the wedding or pictures and she was I admit I am a little bit jealous but mostly hurt I don’t know what to do