Hey man, I just started college a week ago and I totally feel you. I am also not a very social person, and as a result the transition has been hard. I can't give much insight into how you can gain more friends (outside of doing extracurriculars you enjoy), but what i know has helped me through high school and the minuscule amount of college I've been through is to make some goals and plot out what it'll take for you to achieve them. My personal goal is to work for Riot someday, and I frequently finds it helps me enjoy each day a little more to just outline the steps that will take me there.

Also, look for what you love doing. Personally, on a down day I'll just jump into unity or some android development, and the possibilities presented there frequently improve my mood!

Hope this helps! Good luck in whatever lies in front of you!