getting demoted at work?

[Soo]

This past May I started working at a start up company. I was told that i'd be the administrative and communications assistant. My duties would include supporting the president, helping write press releases, monitoring the social media channels, coordinating important meetings. I started the job and realized it was a lot more support work than i thought. The president started referring to me as his executive admin. I suppose he needs one, just didnt realize how much 'care' he needs. He is an extrememly busy guy. He has another start up company, he's a professor, he gets contacted by the press all the time. In addition to working for him, the other VP's in the company come to me on scheduling, then other employees come to be about reimbursments, parking issues, etc. My job is 75% scheduling it seems. I made an error in double booking the president for something. He said yes to two events...then blamed me when i told him they are on the same day. He showed no mercy and that it's my job to manage his calendar, schedule, everything. I get that...but wow, i'm human, i'm doing a lot, it ended up being ok. But last week he told me that he's getting a new admin. I will be working for the VP's. I was upset.
I talked about it with one of the managers here and she said she thinks he needs someone who will really take charge, figure things out before he does, etc. I feel like i'm being treated unfairly. Perhaps i should have spoken up about all the other tasks i was doing. We dont have an HR person here but one is starting next week. The manager suggested i speak with her. She assured me that i'm not getting fired. I've been a support person before, i have a masters, i really thought this job would lead to good things for me, but i'm feeling miserable this week. It's humiating. All the other people here will know. At the same time i am a little relieved that I wont be his go to person anymore. But i dont want to lose this job. Advice??
they are having another dept handle oncoming employees...but there's been no HR person there to document work performance or anything like that.

[Freefromdrama]

You were demoted the boss did not fire you and could have therefore do the best possible work for the Vice Presidents in the company i.e. accuracy and timeliness remaining calm and in control. This will reduce your work load and give you time to concentrate on tasks from the VPs. I would not speak to HR at this time just continue doing a good job so your performance is on par and then either seek another position at the firm or start searching for better opportunities on the internet. Please keep in mind many start up companies are out of business within 5 years. Good Luck!!

[Bane]

Look at your original job description. In it should be your title and job duties. The thing that messes most people up is the phrase, "Other duties as assisnged". It sounds like your job put too much work on one person because they were too cheap to hire another person to take on massive amount of duties. Or it could be that the place was dysfunctional before you got there and that dysfunction carried over onto you. This is why it is a good idea, when interviewing to ask about the person who had the job before you. DId they move on? Were they promoted? Since this is a start up company it is likely that they don't have their stuff together. If it was REALLY all your fault you would have been fired and not just demoted.
I don't know what your manager meant by needing someone who "really takes charge" But I do know that most people aren't mind readers and unless one knows the ins and outs of a business, and that takes time and training then you can't be expected to think for another human being. You said yourself that the place did bot have an HR person when you were hired and one is starting next week. That in and of itself is ridiculous! Who handled your employment paperwork?

[Smart]

Career coaches and staffing experts suggest that, in this cold economic climate, you have to grin and bear it. "At another time, you wouldn't take it. You would just move on," observes Eileen Wolkstein, a New York career coach. "At this point, you have to be pragmatic. The alternatives are bleaker."