Sometimes i feel regret what i'd chose to be.....a nurse

At first, when i started to work, i really did not expect to get into pediatric congenital heart disease ward. It was totally busy ward with one medical officer in charge in that ward. My heart really disappointed and unhappy got into pediatric ward. i felt very jealous to my friends who got into ccu, cath lab and adult ward.
My first impression was i thought i'll be just fine and with full emotion in my heart that i do not like pediatric.
I can't cope with pediatric congenital heart disease because i started to dislike it. when i read and involved in case discussion, i cannot focus at all. The interest does not show up at all.
The work environment and the staff which i don't think they were cooperative. the feedback that i got, i did not seek for help. How i'm gonna ask for help if there are staff who were very selfish and really does not cooperate. In the middle doing observation, i have to fetch pt from invasive cardiac lab. Then i finish my work after 2pm...it was so miserable.
when i'm in-charge nurse, the medical officer which i called crazy doc like to seek my mistake every time. I can't stand in this ward, when i seek for help, they ignored me, then told me that i was not communicate to each other.
I do not have break time at all when i worked in this ward, i went home like office hour staff do in the late evening, my body very tired, i can't revise what i learned, and the working cycle went on like this every day.
I tried my best but still there must be disruption going on until i fed up.
nearly one year, i still not confirmed yet as an employee due to bad feedback, for me if no one saw what's the best that i'd done, i don't mind that kind of feedback, which i don't care at all, i was requested to change ward. Since then, i really hate it, the staff , crazy doc and even the nurse manager. Now they put me in the PALS exam, till now i don't read the PALS book that much, because my heart is totally close for it. I don't want it at all.
Now i'm working with staff which more cooperative and i able to remember all pt case, have courage to speak out to doc or call for help, they were really helping me. I am really thankful for that.

Now i'm still thinking what i'm gonna do wit the PALS exam? I feel like to fail it. if i fail it i might be regret later on right? how??