Ryan,
Good for you!
Things will eventually calm down. As a bi dude, my family thought I was going through a phase which was sorted out by my getting married. I hope one day that marriage will be available to you as well, as it's been very good for me. Except when it sucks, but that's another post.
My best advice is tell your closest friends and family first, and then let the rumor network do its thing. I find that my dual earrings will give most people the clue they need to work it out if they don't already know. I'm sure that if you've gone through hell at high school, then most likely most folks have their gaydar triggered with you, which is good. Just be yourself, and have fun.
If you want a funny movie to watch about being trying to be "converted back", check out this z-grade film.
http://www.imdb.com/title/tt0179116/
I don't think your mum will ever stop trying to make you straight (as if it's possible). I know my parents didn't. Don't let it get you down. There's a number of GBLT and friendly folk here, so feel free to talk about anything if you're not getting the help you need.
ps. there are GLBT shrinks out there too, you don't have to put up with a therapist who is trying to cure you or (more commonly) has no real understanding of your issues.
thanks,
Andrew