This is such a horrible situation, but sadly, I'm sure it's not the first time you've experienced this sort of behaviour from your mother. My advice is to re-read the post made by KHerbert and follow it exactly. This poster works in a school, and has likely seen this type of situation before. Get yourself a good family court lawyer now, and follow their advice. I would also seek therapy, either through a therapist or a religious person you respect or some other venue, not just here online. You need to talk to someone face-to-face and have them tell you you're okay, you're doing the right thing, your mother is toxic. I would also advise not posting anything about this or your family on a webpage or blog or myspace page that can be traced back to you. Putting anything out there where your mother can read it will only continue to fuel the fire. I'm assuming she doesn't belong to this board, so that's ok, just don't respond or react to her in any way other than calmly and coolly. If you let her know she is getting your goat she's just going to keep stirring things up. As a previous poster said, if she's not getting a reaction from you she'll move on to other things.
Turn off the computer for a while, sit down with a piece of paper and write down a plan, i.e.,
1. Call police and file restraining order.
2. Find a lawyer.
3. Get proper forms notarized and copied, and submit them to school personnel.
Seeing it laid out might help make it seem easier to deal with. Hang in there. This is one of those, "What doesn't kill me will only make me stronger" life-changing events. Once you're on the other side of it all, you are going to see how strong you really are. ((((((hugs))))))
PS You might want to find a song that makes you feel all, "Yeah!" whether it's "I Will Survive!" or Metallica or whatever... play it whenever you need to be pumped up. When I was dealing with a serious illness I found listening to the same songs over and over made me feel more optimistic about getting through it.