Yeah I know where you're coming from, my university had 7k first years alone, and 35000 students total
It's definitely a whole different atmosphere, but I'd say to get as active as possible. I did intermural sports and it was a sick way to meet a lot of new people with similar interests. Idk, go to events, go to bars or something if you like that sort of thing, just do anything. As long as you're trying, you're guaranteed to meet a lot of cool new people that'll hopefully stick with you for the next few years of university at the very least.