Going away to college is scary enough. It's even worse when you're an introvert. I've never been terrible at making friends, I've just been selective. If I'm around a lot of people with a lot of energy for a long amount of time, I start to stress and shut down. But making friends in high school is a lot easier than making friends in college. In high school, you're thrown into a class with 20 or more other kids your age and are given time to freely speak to each other. You then spend the next eight hours surrounded by pretty much the same group of kids. You bond over things like hating the teacher and what guy is cute.
College is a little different. The first person you meet and probably the first person you'll consider a friend is your roommate. Hopefully, you develop a good relationship as you'll be living together for the next nine months and will have to spend quite some time together. Then there's a weird limbo in between the time you move in and the time classes start. You are constantly meeting new people-- the people on your floor, the friends of the people you meet, who you sit next to in orientation lectures, the girls in the bathroom. But you probably won't feel a connection with any of them and this can be draining for an introvert. Small talk sucks and that's what the first few weeks of college are. You complain about the water pressure in the shower and talk about what guy is cute. Then you start to realize it's not that different from being an introvert in high school.
Eventually, classes will start and you find some people that have some of the same interests. Then you start joining clubs and you find even more people with even more interests. And, unlike high school, you can remove yourself. The most socially draining part of high school was constantly having to be surrounded by people who wanted to talk. In college, if you're not in class, you can very easily find silence and solitude in your dorm or a coffee shop or an abandoned corner of the library.
Being in an introvert in college is about putting in the time to be a productive introvert. Spend the first couple of weeks feeling people out. Listen to what people say when they do those annoying icebreakers; maybe they like the same band or TV show. Being an introvert in college is about finding a few friends that you enjoy being around and that don't drain you and sticking with them.
Being away from the people and the life you are used to is scary and overwhelming, but learning how to function in a new place by yourself is one of the greatest adventures of all time. And always remember that everyone else around you is just as lost, so just take a breath and enjoy the ride.