I recommend the on-line ENA questions bank/review. I admit I passed the first time, and I am a good test taker - but, having an idea of question format, and just drilling on them over, and over, and over, really helped! Good luck!
I've been in the ED for almost 2 years now. I got chewed up and spit out at one of the facilities in our group. I had to look up stuff on my own because some felt that a question was stupid, or they wanted to "toughen" me up. Now, I've watched those same people leave a brand new to our ED charge nurse with practically no staff saying the same thing. I think sometimes that we forget that people need to learn. I don't work in a Level 1 - though one day I will - but it seems to me it is about the people themselves. I still feel like a noob, but now I'm a CEN, I handle my workload, and one of my precepting nurses prefers for me to be charge because I handle flow better. We grow up! I swear! Try for patience. And ENJOY your vacation.