The material will start to click eventually. Law school is a big adjustment and it takes some time. I understand how you might feel overwhelmed, but just keep grinding away. Try out different techniques - if you’ve been reading after class, read before, or vice versa. That might help. Also, don’t be afraid to either ask questions in class or shoot your prof an email. They are there to help you if you don’t understand what’s going on.
As for the people situation, I’m not sure what to say other than your cohort sounds very immature and it sucks that you’re stuck with them. Keep making efforts though. I’m sure if you said “hey, I don’t have anyone to discuss this with, mind if I join you?” they wouldn’t turn you away. They’d have to be total pricks to do that. Law schools are definitely all super high schoolish and so I understand where you’re coming from. Given that the cliques have already started to form, just keep trying to make a conscious effort to talk to people before or after class. Maybe try and find a study group. ECs are also a good way to meet people. Join some clubs or sign up for a moot. If your school has intramurals, join a team. There’s lots of ways to meet people outside of your cohort too!
Best of luck.