My boss hired a replacement for me?

[A Hunch]

I keep seeing you post variations of this story...
And I keep shaking my head = why do you want this job? why did they hire you for this job?
You have a master's degree. You aren't a professional executive assistant. I don't see that as what you want to be. And I think the company made a bad fit in selecting you for the position. So they figured it out and now want someone with more experience. And, what??

Why don't you figure out what you want your position to be? Do you want to work in social media? Do you want to do the scheduling? Do you want to do special projects? When you figure it out, you can talk to the HR manager about how to make that happen for you.