you've told someone now - us who read this messageboard. that's the first step.
you're right in thinking that you need to tell someone close to you like your mom or someone you trust who'll take you seriously. you could print off what you've written in your post. most people would be moved by what you've written and if they don't get it, it says more about them than it does about you.
it'll also be worth getting yourself checked out medically at some point to make sure there's no physical problem with your bowel function as well. (but by the sound of it you can go fine if there's no-one around?)
at some point, the doctors are probably gonna offer you anti-depressants or some other psychotropic medication. my advice is don't take it. you have the right to refuse it.
why? because the claims made by pill manufacturers are basically dodgy. if you wanna read up about it, try 'bad pharma' by ben goldacre. or just read the news that comes out periodically about pharmaceutical companies using dodgy means to push their pills.
this from the bbc yesterday:
GSK bribery network
i went down the pill route myself and believe me, it just makes your situation worse in the long run.
i've just written a post on meditation called TM story. i know, know, it doesn't sound like meditation would help shy bowel but you might wanna read it anyway.
good luck and bless you
feel free to write back