It's a difficult situation. (I know, my boss is like that, too.) Unfortunately, there isn't much you can do to change the way she treats you. The first and best thing to do is to maintain your professionalism at all times. I've found it's best to simply "not hear" my boss' digs and threats if at all possible. Often they aren't direct, but come in the form of spin put on legitimate statements and comments about work. In that case, I respond only to the legitimate portion of the question or statement, and again pretend I didn't hear the tone or phrase that made it more. I've also gotten good at giving responses that acknowledge that I've heard what was said without agreeing or supporting it. A bland "I understand," "I see," or "okay" often seems to appease her. For your own protection, DOCUMENT EVERYTHING. Hopefully it won't reach the point where you need it, but if it does, having contemporaneous notes (made at the time) will carry more weight than simply recounting events from memory. If you have Human Resources or an Employee Assistance Program where you work, you may want to approach them about the situation. If you do, don't go in complaining about how you are treated. Instead, approach it as needing assistance in coping with a difficult situation. You might also see what kind of counseling your school offers, as a counselor can help you find ways to deal with your boss effectively while minimizing the impact she has on you. And, when all else fails, you can do what I'm doing: start looking for another job. I understand that it's not always the most practical answer (it sure isn't for me!) but I've finally figured out that life is too short to spend that much of my time around someone who treats me that way.

Report her to the Human Resources Manager citing documentation of her statements and the times and when they occurred. If this doesn't work, quit and get another job. There's no reason to remain within a job that is only making you stressed out. After all, there are other jobs where you might fare well and have less stress. Clearly, this person needs to grow up and is jealous of the fact that you're getting your education. If you do quit, then tell her, "GROW UP!" Good luck!

Use that degree to apply to a position above that boss, that should put them back in their place. If that boss is the only person who runs the company, start your own.