Feeling anxious can be caused by many normal life situations, such as a big test at school or learning to sky dive. But when anxiety seems to hang around all the time, it can take over your life. This article from a trusted source helps you to know just how much anxiety isn't normal, and the treatments available for this problem.
Do You Have Social Phobia? by WebMD (2016)
We can all feel nervous speaking in front a group or going to a new school, but this article explains how things like avoiding eye contact or constantly avoiding all social situations could be more than shyness. Social phobia causes intense fears with physical symptoms, and the sufferer may feel like a prisoner to his or her feelings. But there is help for this condition.
McDonagh, T. (2016). 101 ways to conquer teen anxiety: simple tips, techniques and strategies for overcoming anxiety, worry and panic attacks. Berkeley, CA: Ulysses Press.
Check out this book by a licensed clinical psychologist for information and helpful tips about how to deal with the many symptoms caused by anxiety. With all the common things that stressful teens deal with these day, this book might be just what you need.
Shannon, J., Shannon, D., & Pedesky, C. A. (2012). The shyness & social anxiety workbook for teens: CBT and ACT skills to help you build social confidence. Oakland, CA: Instant Help Books.
This guide can help you learn to handle difficult social situations with confidence. Cognitive Behavioral Therapy or CBT is an effective way to overcome extreme shyness, but anyone can learn to improve their social skills and benefit from this book.

What are Anxiety Disorders? by Khan Academy. (2016)
This article from Khan Academy describes the reasons why fear exists, and when it becomes a disorder called anxiety. It's OK to be afraid! But when fear begins to take over your life, you may need help.