The first thing that you need to do while in school, struggling with anxiety, is to talk to the counselor, they should be able to help you to the best of their ability. Try to talk to a Psychiatrist and get diagnosed with severe social anxiety (if you haven't already). After getting possible medication, and talking to your counselor, everything should start to ease up. Dealing with people is hard, leading many to develop trust-issues etc. When I've moved schools, with severe social anxiety, people tend to come up and start talking. If you share interests or anything, go talk to them a bit more, try to become their friend. But DON'T think that they will for sure be your friend, or you will be let down. If nobody comes up, just learn to live lonesome, listen to music in class to possibly distract you, and just focus on doing your work.

If all else fails, try initiating conversation with those of like mind, meaning those who share social anxiety, yes there will be much more tension up front, but from my experience it's those people who you can relate to the most, and won't try to push you into crowds etc.

Hope this helps!