You're not alone. I was the victim of verbal abuse regularly throughout elementary and middle school. This not only destroyed my ability to socialize in a healthy manner, but also purged any ounce of self-confidence and self-worth that a healthy individual should posses. It also destroyed my desire to do well in school, as I was typically more pre-occupied with being made fun of than I was with paying attention in class. As a result, I was consistently failing and barely passing my classes in school. In High School, kids got much less confrontational (not everyone's experience, just mine) and instead of making fun of people "they" didn't like, you were simply ignored. This kind of "shunning" was in some way just as bad as the bullying I experienced beforehand, and further encouraged my social exile from humanity.
I experienced my first "break" in Senior year, after being assigned to a weight lifting elective. I couldn't work up the courage to actually go to the counselors and select my electives for the new semester. If you didn't select your own electives the school would assign them to you at random, but I was absolutely opposed to spending any more time at school than I had to so I never selected them. My experience in weight lifting was an immense boost in confidence. I lost weight, got in much better shape and people began to actually notice me, which in a way tells you how fucked up people are. With my slightly improved confidence, I started being able to actually talk to some people and made a few friends. Our little group was all alike in that we were the outcasts of the school, but they were good people generally. I found a job at a local grocery store, which actually helped even more as I was forced to interact with people everyday. I finally started to develop social skills that had escaped me for so long. I learned how to approach people, how to greet them, and how to make general conversation.
I still struggle with it somewhat, but not necessarily anxiety. Because of my life experiences I've become a very cynical and jaded individual, and can have difficulty relating to others.
You're not alone.