Anxious wreck of a new grad

I am 3.5 weeks into my new grad in a busy post-op ward. I had a preceptor supernumerary time for one week. She is still supposed to be my preceptor however she only works casually, so the days she's not on (most) it's someone else. They are not buddied with me, but float on the floor, have their own patients (usually about 5) and are there if I need to ask a question. The thing is, my "preceptor" disappears with no notice, today I couldn't find her for 2 hours. In the first week it was so busy, I hardly got told where the toilets were, let alone the ins and outs of pre-op admissions, post-op orders, etc etc. I feel like everyday I go in, I am waiting for someone to point out something that I have missed. Each time, I jot it down and write it on a list to remember, but each day it's something else, and I am blamed for it. I don't understand how I can be blamed for the mistakes, when I am completely unaware of the protocols or how the unit runs- I just feel an overall complete lack of support. I am trying my best but I am coming home in tears each day, shaking and feeling anxious about the next shift-what else can go wrong, when an incident form will be put in. It's not that I am purposefully making these errors, I just literally do not know and my "preceptor" seems to get cranky at me whenever she has to show me how to do something new-she gets distracted and goes to meetings or has to help others. I am at a loss because this is the only grad program I was able to get into as the public cannot accept me as it has been over a year since I graduated. I know I have to push through it, but the lack of knowledge of how things run is really getting me down. Any advice would be much appreciated.
Each time, I jot it down and write it on a list to remember, but each day it's something else, and I am blamed for it.

That was by far the best thing I needed to read. Thankyou very much. I get told that a lot. I am by far the biggest perfectionist and harshest critic of myself, I just hate not being good and efficient at things. But I know it takes time, it is just frustrating. Thanks so much!

Being a brand new nurse is probably one of the most humbling things you will ever go through. You want to look good, you want to be perceived as competent, you want to shine.....but the truth is you AREN'T competent yet and nobody expects you to be. You will be getting a lot of feedback, which is a good thing, but for perfectionists like you and me and most other nurses, it is a raw experience that can be frustrating and discouraging. Make up your mind to deal with this temporary career phase with grace. Accept all corrections and criticisms with inner grace and implement them into your practice. Don't let your brain fool you into thinking "Everyone thinks I suck! They probably are talking about me behind my back, about how bad I am at this!" It is a dangerous mental pathway that will do nothing but obliterate your budding confidence. We were all new once, every single one of us, and where I am from, more of us are trying to bend over backward to help build that new nurse up. If she is particularly hard on herself, she makes that hard to do.Congratulations on your new job!