Hi Laska,
I'm so sorry you're having such a bad time.
Do you have guidance counsellors in your school that you could talk to? How about a teacher you feel comfortable with? Is there a crisis phone line in your area, especially for kids and young people? (Here in Canada there is Kids Help Phone.)
These might be some places to start. Your doctor could also be someone you might talk to.
But mostly I'm curious why you're so scared to tell your Mom? What are you afraid might happen? Your Mom might surprise you. How about writing her a letter telling her about it and giving it to her to read? Start with what you've written here.
I don't know where you got the term "social phobia" but you sound like you have a pretty sophisticated view of what is bothering you. You can use that ability to find the words to tell your Mom, too...or any other relative you feel comfortable with, if that's just too scary.
Most important, you need to get some professional help for this, if it's that crippling for you. You need to talk to your doctor, a guidance counsellor and/or your Mom...whoever you have to, to get some help for this condition.
DO NOT TAKE AN OVERDOSE OF PILLS FOR THIS! You could really hurt yourself by taking excessive vitamins, even though it seems pretty harmless. Yes, I suppose getting sick from is one way to deal with the situation, but it's not healthy and it WILL create WAY more problems than it solves. You want to help yourself, not make things worse.
Good luck. Let me know how you make out, okay?
TheOneInFour