Need advice on How to resign gracefully and keep my career

So I had a feeling I was going to get let go. Mange to come out of the meeting with less than a month to piece my plan together before they boot me out the door.
So I am a fairly new grad with the less then a year experience and just started my first full time job a month ago. I have 2 previous temporary jobs as a nurse that were time limited and I did a good job at. So I had my 3 month review which was good an After this review my boss goes on a two week vacation. When she arrives back she pulls me in her office do to multiple complaints from coworkers most of which were elaborations on events or straight up lies. I took responsibility for the things I know were true and didn't place blame...which I could have done.
So now when I asked for shadow days to help me progress and meet the demands of my meeting . They used it as a way to test me and find reasons to let me go rather than help improve upon my skills or provide me feedback . So after my shadow days they pulled me in the bosses office and nit picked every thing I did. The boss then end up telling me she rather see me go then other staff because thats the direction this is going. So someone gave an ultimatum and now I am less than a month from the door. They have not let me go yet but I feel it in my best interest to resign.

So how do I exit this situation gracefully so I can get another nursing job?

What steps do I take to protect my self?

How do I survive the next month?

Any help and support is appreciated. I feel so alienated and set up for failure.

Thanks