I have been reading on the allnurses forum for a while and I finally had to make an account on this forum after reading your post. I was diagnosed by my doctor to have social anxiety. First, I would like to encourage you to stick with nursing. Even if you switch majors, you will not be able to escape being in groups with other people.
What has helped me cope with my social anxiety is to just accept it as being a part of who I am. I have noticed that by doing that I am not as nervous being around people. I liked the book "Overcoming Social Anxiety and Shyness" by Gillian Butler. She goes into explaining the psychological cycles that take place with social anxiety and and how to correct those cycles. It was interesting to read so you might want to check it out. Also, my doctor prescribed me a medication called propranolol which has worked wonderful for me when I had to give speeches in my communications class. You only take it like a hour or so before your presentation and that's it, you do not take it daily. It eliminates the physical symptoms of social anxiety such as getting a red face, sweating, and the heart pounding out of your chest feeling. I thought it worked wonderful for me. I don't know how I would have passed my speech class without it. Do some research on it for yourself and ask your doctor what he thinks of it for you. By the way, I am against long term medication for social anxiety because it is only masking it. Once you stop taking the medication, your social anxiety will be back. My doctor wanted to prescribe me Paxil but I refuse to take it. Anyways, I just want to encourage you to stay with nursing. The way I try to look at it is that what is the worst that can happen. My face gets red and I feel embarrassed if someone says something about it, but in the long run what does it matter. Two years from now, will I even remember that situation or will I see that person ever again? Most likely not. Walk into class like you own the place and forget what other people think about you. Hopefully at least one thing I have said has helped you. Good luck at school and keep your head up.