If you transfer, what will be different? Please read this. I wrote it after my daughter had a hard time adjusting. She is an introvert and sounds a lot like you. She is now a happy senior.
http://talk.collegeconfidential.com/college-life/2016222-to-those-who-feel-lonely-homesick-friendless-think-they-chose-the-wrong-school-etc-p1.html