As for your co-workers who complain about their assignments when you are in charge, turn the tables on them, ask them how you you have made up the assignment?
I had one mean b*#ch come up to me and have the audacity to tell me "You can't make the tough decisions." She was angry b/c I gave a lesser experienced nurse a challenging pt (OK, the pt was a no code on CVVHD, and I figured, she could learn, and if she screwed up, at least the pt was a No Code) I also had a very experienced nurse who was a float to support the newer nurse. Mean nurse thought I absolutely should give the tough pt to the experienced nurse and let the new nurse float, which in my opinion was useless, what can she do if I really need someone strong? So, yes, she told me that in the middle of the unit in front of my peers. She was testing me. I passed. I stepped right into her face, and she was very tall, and I am short, so she leered over me, trying to further intimidate me, and I said, When it is your ship, and you are in charge, you can run it your way, and when it is my ship, I'll run it my way. Then she proceeded to loudly complain about me to everyone, esp her best pal, who loudly agreed with everything she said. It was the weekend, the next day, and I swear it wasn't on purpose, but they way the 12 hour and 8 hour assignments were, I had to give her best buddy a new admit, and she had another pt who was on a vent. She complained loudly to me, and I simply looked her in the eye, smiled and said, well, this is one of those tough decisions I have to make, sorry. They NEVER bothered me again! LOL!
Not to make light of your concerns, but you will learn. If you never are in this position, you will never learn what to do. You are still green, and that is why you are feeling insecure, I don't think it has anything to do with being a "bad" charge nurse. Being in charge blows!!!!!!! I HATE it, truly, the most thankless job in the world. But, as a RN, it is part of your responsibility and you will have to do it sooner or later.
If you feel you are in a situation where the less experienced nurses and yourself are unsure of what to do, you need to find out who your resources are now. Are there other ICU's, like the MICU, PICU, etc, with nurses you can ask advice when you are on duty? Does your supervisor have critical care experience? Are YOU ACLS certified? Who is the best at reading EKG's? Who is the best at starting IV's? Who is the best IABP resource? Call your manager at home if it is nights, ask her what to do if there is a problem. During a code, yes you should know what to do, but ultimately, it is the docs who write the orders, Yeah, I know, some of those residents are greener than you, that's why you need ACLS if you don't already have it. Make a plan for how assignment will change if you are hit with the unexpected, have to triage etc. When you do advanced planning, you save time worrying about what you would do. Propose scenarios to the other charge nurses and ask them how they handle things in the same situation.
I had to be in charge of my 42 bed med-surg floor the second day after I passed boards. It was horrible, but I just asked questions, and I'm still here to tell about it.
The bottom line is, and I apologize if I offend anyone here, you need to grow your b*lls when you are a charge nurse. It is not an easy job, all the doo-doo rolls down onto you, that doesn't mean you have to be someone's whipping girl or boy. Explain why you made assignments the way you did, if you can. If you are busy, tell them, I know you're not happy, but I can't talk about it now. I need you to help me out with this, and I'll talk to you later, then do it. Do you also have to take an asignment while in charge? That is the pits.
I could tell you a hundred stories about being in charge, how many times I was challeneged by my "friends", how some people love this and it is a little power trip for them, and other of us, like you and me, just want to get our shift over with and take care of pt's tomorrow. Probably just about anywhere you go as a RN, you will need to be in charge at some point, I think it is surprising that you have been given a year without having to. You are doubting your own abilities, and maybe your manager sees things in you, your growth, that you can't b/c you see only all the things you still have to learn, and are forgetting how very far you have come already in the last year. Maybe she is giving you the little push you need b/c you would never do it yourself. There is never really a good way or a right time to learn how to be in charge, it is trial by fire usually. I hope some of what I said helps. If it is really horrible, you need to talk to your manager, and don't be afraid to ask questions, even if they feel stupid, it's the only way you will learn. You will also be surprised that many nurses would do things different ways. Give four nurses the same charge nurse scenario, and you will probably get four sets of assignments. There is more than one way to do things, you will find your own style. Just don't be a phony, that is my personal advice, not anything you will find in a management book. People can see right through BS! Good luck, I have faith in you!!