Only
32 percent of the Ole Miss campus is Greek, according to the Office of Admissions. That's on par with what I've heard from previous years, too. I've also known many Ole Miss students who did not join a social fraternity or sorority (though most of the students I knew joined some sort of professional, service, or honorary Greek-lettered organization at some point before graduating).
It's not easy to make friends anywhere. Even in structured organizations like fraternities and sororities, it takes effort to get to know new people. It is often easier to meet people when an organization is structured around social events and plans them for the group, but that's not the only way to meet people. There are other student organizations that are focused on specific interests. There are the new living-learning communities and freshman interest groups--while not perfect, they provide a structure for interacting more with students in your residence hall. If you enroll in
EDHE 105, that can be a great way to meet people, too.
The social atmosphere, to a great extent, is what you make of it. If you go into the experience expecting that you won't meet anyone and it'll be miserable, that's probably what you'll find. If you expect that you'll meet lots of people through classes and organizations and it'll be great, that's probably what you'll find. You might feel like an outsider. You might not. I can't really say. But there are a lot of opportunities beyond the Greek system if you're willing to seek them out. I promise.
(Seriously, though, enroll in
EDHE 105 your first semester if you can. It helps a lot with adjusting to campus, it's usually a GPA booster, and you can learn about different activities and ways to meet people through your experiences in the class.)