Feeeling down about work...what should I do?

You should DEFINITELY have an honest conversation with your manager about this person. As I understand it, this person isn't even an employee of the company (but is a temp employee?). Don't use the words "hostile work environment." Those words bring up so many emotions in HR. Just explain to your manager that this person is consistently rude and demanding with you, and that she has threatened and repeatedly demeaned you, and that you don't feel "safe" around her. But play the role of the 'good guy' here. Tell your manager that you really DO want to get along with this person, but that you need for it to be a two way street. Honesty is the best policy. You're not complaining if it is making your job and the environment more difficult for you. HR *wants* to know when this kind of thing is going on. Good luck with your situation.