Discluded in friend group

So my friends always leaving me out, and I don’t know if they don’t mean to but it always makes me feel some type of way. I always try to include them when I do something or when I see that no one is paying any attention to them, but then they disclude me in what they do and the conversations they have. We have a group chat, and today we went on a trip, where they sat together, and had made whole plans etc about what they were going to do on the bus in a group chat with me and them. That made me feel left out but it made sense that they were sitting together because I previously said I wasn’t going to go on the trip. But then ig they talked about doing some community service during the weekend, and later today they have a whole conversation about it, and it made me feel bad because when I plan to go out with a friend I try to invite everyone else to not make them feel left out. I wasn’t even aware of it, and it made it worse that they didn’t even tell me or invite me, and it’s only me and them in the group chat, so basically it was a conversation between two people that I couldn’t join. I don’t know what to do, maybe I am taking it too personally, or maybe they are just close, but I always try to include them when we are with others, and never just one thing with one of them and not the other, but they don’t do the same for me. I really just needed to vent so if you read this thanks!