New PCNA, need a nurses input/advice

Hi, I am a new (within 90 days of orientation) PCNA on an ortho floor in Cleveland, Ohio. I received a 45 day review that said that I was doing very well and that there were no concerns at this time. The only thing the manager said was that scheduling could be an issue as I am in nursing school. I have worked in management in retail, so I realize you have to put SOMETHING down as a potential "needs improvement." So after that review I felt pretty good and have continued working as I normally do. Fast forward to almost my 90 day review and I was called into the office and I was given a laundry list of grievances from 6 RN's (which would be all of the nurses that I work with on my shift). The list basically encompassed my ENTIRE job description. I was in shock and very upset. I would say that 90% of that list was not true. They said that I didn't answer call lights (I am the first to answer a light- mine or someone else's), I don't take vital signs in a timely manner (which I take at 1500 and 1900- yes, I could get them into our charting system earlier, but I find answering call lights more important as our patients do not have bathroom privileges and I do not want to make the patient wait, so I will make it an effort to get them in the computer faster (i can work on this); I was told that I do not fill ice bags or water pitchers (which I do, but I do admit that when all of our patients are 2nd days post-ops and they all need to use the bathroom and each pt takes 10-15 minutes to toilet- ice bags can get behind...when it is not as hectic, those ice packs are filled 3-4 times on my shift- and I refill water pitchers when I come on 1500, dinnertime 1700, usually around 2 vitals 1900 and usually once more before I leave; I was told that I do not turn patients, do not do accuchecks in a timely manner, I have an attitude (this really made me upset because I do every/anything the nurses ask me to do without protest... so maybe it could be non-verbals???). Basically, I was told by management that they were extending by probationary period for 30 days and if I do not show improvement then I will be terminated. I am very upset because I LOVE this job, the patients, and I really like the nurses (even though they are notoriously tough). I DO NOT want to get terminated and the people that I talked to about it said that I should just quit, and I do not want to do that either. I spoke to one of the RN's that night I had the talk with management and she basically said she had never complained about anything of those things and that she felt ALL the PCNAs could do a better job filling ice packs and water pitchers. That was my only advice. So yes, I will be all over the ice packs and water pitchers, but I am at a loss on the stuff that I already do but am being told that I do not do. Also, I guess that the nurses do not like it when we sit down to chart- which I do. It was recommended that I do the charting in the patient room. I am bothered by this a lot. I do not get on facebook or check my email, I am using the computer for work-related things that are to be done. I talked to all of the other evening PCNAs and they said they all have went through this as well... so I guess that makes me feel a little better, but I work my butt off all night (sometimes I don't take a lunch) and I feel like it's all for nothing. I guess my questions for all of you nurses is: What makes a great PCNA at your job and any suggestions for improving. I am open to any advice at all that will make me a better PCNA. Thanks! (sorry this is so long winded)