Oh I completely feel your pain! I have been there, done that. One of my previous jobs was as an Office Coordinator...fancy name for Admin Assist, fancy name for grunt.
And I LOATHED my boss and she felt the same way about me. It became obvious after a while that I was only there to entertain her and her in office buddies. I had tons of work that actually NEEDED to be done, but she'd always keep me hoppin' with something else. You can't imagine.
I remember the straw that broke the camel's back was when I was really sick, but at work anyway and she sent me on an 'emergecy' trip to Sam's in the middle of the day, in 100+ heat to pick up something--I got there and found out it was a fake office plant! Got back to the office and she put it on her office shelf and said that she'd wanted it for decoration!
And the owner of the company was just as bad. He was having a mid-life crisis and would come up with bizarre requests--once he said, "find me an air purifyer that smells like the highways in California" Huh? And once it was, find me a mural of the stars for my office ceiling and a chair that will mount to the wall so I can recline and look at them while I work. And he was dead serious about this stuff!?
I let it get to me at first, but then figured out it was more fun to make her miserable by killing her with kindness...hey, the job paid well! I knew they were downsizing and they'd been upfront w/ me 6 months in advance and told me my job would be eliminated. I had plenty of time to get my affairs strait, another job lined up and just had to sit back, drive her nuts and wait for them to make the cut so I would get a nice Severant's pkg. If I'd let her get to me I know the $$ would have gone in her pocket and I'd have gotten nothing (which is probably what she was hoping would happen.)