To me this reads like you might have some social anxiety…if you have found yourself limited in what you do because of anxiety, maybe now is the time to get that addressed. Have you ever not wanted to go somewhere because you would have to go to go alone? Have you ever not done something (perform music) because it would be in front of many people?
Also you are going to have to invest time in making friends…see this post for tips.
http://talk.collegeconfidential.com/college-life/1808143-having-trouble-adjusting-to-college-making-friends-top-10-things-to-do.html#latest
Try to get involved in many freshman orientation activities as possible.
Go to the counseling center (http://www.swarthmore.edu/counseling-and-psychological-services) early on…they will have programs to support freshman. You are aware that you might need more support than the average freshman…take advantage of it!