You sound to me to be suffering from what is known in the psychiatric world as agoraphobia. It literally means "fear of open places" but that is not what agoraphobia is. In a nutshell, it is anxiety caused by feeling "trapped" in a situation, whether it be at work, home, at the supermarket, etc. I have anxiety disorder and have suffered from agoraphobia as well. It can be quite debilitating and can manifest itself in physical ailments when the anxiety becomes intense enough. You really need to speak to a psychiatrist and/or therapist and get some help for this, whether it be relaxation techniques or counseling, or if all else fails some tricyclic antidepressants can help with this.

Here is more of an explanation of agoraphobia, but you can search on the net and find more about it too and see if that is fitting what you think you're feeling.

http://pages.infinit.net/drnayman/agorapho.htm

I wish you the best in this and hope you are able to find some help. I know how miserable it can be to suffer such intense and debilitating anxiety. It also began for me in school.