Educational istant having problems with the teacher?

I am an Education istant and I totally hate my job! I can not quit because this is my only source of income and there are no other jobs for me to take right now. I am 26 and she is really old. Well I am also black and she is white and she acts like I am a personal slave and a student! She even try to get in my personal life and question my where abouts throughout the day at work. What should I do because I don't want to confront her because she is old but I want her to understand that I am an adult too and I do not work for her...i work for the school system to help her. I do ALLLLL my work plus extra stuff for her! I have already talked to the Principal about her and he had a talk with her once before about her behavior towards me and she apologized and said she was just having a bad week so I let it all p. I don't want to seem like a person who can not handle my own problems so I really don't want to get the principal involved again....what should I do? Serious help...no smart remarks or bs answers please.