OP- I hated HS and loved college. The bar for “casual friends” is very low in college- you meet someone standing on line for a waffle at breakfast, you are both taking Econ, voila. It may not be a friend forever, but when you walk into the lecture hall the next day, there’s someone to sit next to. Nobody knows your history, nobody knows your family, everyone is a fish out of water.
I have no doubt that you will find people to bond with- and over time, these relationships (some of them) become real friendships.
re: Italy with your HS class- why not decide later on once you see how the class is going? It’s no fun hanging out with a group that’s ignoring you, but it’s GREAT fun exploring a new place with people who want to explore with you. You don’t have to commit now, do you?
And college travel is completely different! You’ll have people from different grades, sometimes the only connection is “I’ve always wanted to see Versailles”- someone who is studying architecture, the folks majoring in French, a senior writing a research paper on violent revolutions in Europe, a freshman deciding on Art History or Biology, depending on how the trip goes!
You’ve got this. It DOES get better.