Hi there. I don't have any specific advice for you per se, but I just wanted to let you know you're not alone. I am a new grad in ICU, completed orientation, and have been on my own for going on 2 months now, I think. I definitely went through that "Dear God, what have I gotten myself into?" stage, as well as the "why-oh-why didn't I just go into med-surg?" and the "visualizing giving my 2 week notice" stages.
That said, I am still nervous a lot of the time (ok, ALL the time), but I am recognizing that I do learn something (usually several somethings) every single shift. It may be where to find something, asking a more experienced nurse about a judgment call, whatever. Some of the questions I ask make me feel dumb, but you know what? Next time that situation comes up, I know a little more about where to find what I need, or how to critically think through it. I try to give myself credit for the small victories.
There are still days where I come home thinking "There is no way I can do this." But then there are also days where I think, "Hey, I caught that! (whatever the condition might be). I did the right thing, called the doc, and now we're on the way to helping this patient." You take those days and really hold onto them. Give yourself credit for what you learn each day, and cut yourself some slack now and then; try to be patient with yourself.
If I get the vibe that someone is annoyed by me asking a question, I try to bring a little levity to the situation or, if all else fails, I will simply say, "This might be a dumb question, but I'd rather ask _____ than do something wrong and harm my patient." That's pretty hard to argue with. At any rate, you tend to find out which nurses you can go to with certain questions. Keep an open mind, though...some of the nurses I initially thought were grumpy/crotchety have taught me the most.
I recognize that I will be slower than experienced nurses, and I will be more "scatterbrained" (going in and out of the room more), but I am working on organization along with everything else. So I'm right there with you! Hang in there....I keep telling myself experience only comes one shift at a time, and it seems 99% of success is just showing up. Hugs to you!