First, don't panic. A bipolar diagnosis doesn't mean you will go off the deep end necessarily. I'm an English teacher myself up north of Dallas (I graduated from Alice by the way. I know your neck of the woods.) I've been able to work and carry on with life pretty well.

The healthcare issue is a problem. You don't have insurance through your school district? I'd go ahead and make an appointment with a doctor through MHMR. You can always cancel it later. In the meantime, if you get just too depressed or suicidal, go to the ER. Don't let things get out of hand. I think someone else mentioned maybe finding the DBSA chapter in Corpus and seeing if you can get involved with them.