Sending 's - she definitely sounds like an awful boss! No-one should have to put up with that.

It depends on where you work but are you able to depend on your co-workers (and them on you) as much as possible and only deal with her when necessary? I remember from a job I had with a useless boss (not necessarily mean but just didn't have the knowledge and experience for her job!) that I just worked with my co-workers for peer support and supervision and only went to her when absolutely necessary.

Also depending on where you work but is it possible to try and get your tasks in writing? That way if she tries to change her mind the next day you have tangible evidence of what you were doing and why.

I really hope you can find something else soon in your job search!