Well, I strongly believe that each nurse, while able to share many common experiences with others in the same place, is different and handles his or her experiences differently. Opportunities that are open to each person will be different as well. What you are feeling is important, and you need to do what feels right to you, and is a decision that you can feel good about.
I can, however, offer my experiences thus far...
As of tomorrow, I will have been in my level III NICU for 10 months (including my preceptorship). I'm still so new and green that I practically glow in the dark I, too, have had feelings similar to the ones that you are describing, and I'm told by my coworkers (who I find wonderfully supportive) that this is common and experienced by most, if not all, nurses new to NICU.
In the past, I've gone home and tortured myself on the drive home about things that have happened that day. My sleep schedule (8-hour nights at the time) was incredibly hard to deal with and keep on a proper schedule that I desperately needed. I'd wake up mid-sleep, I'd dream about work and hearing bed alarms in my dreams, and I'd even wake up with the feeling of "Oh no, I'm late to do a hands-on assessment of my baby!). There were times when I thought I was the only goof who had these experiences. I did wonder at times if I was experiencing depression or that "adjustment" difficulty that I've heard so much about that many new grads experience.
Well, turns out I'm not alone, thank goodness :) There were several things that have helped me out so far:
1) TIME! This is hokey and cliche, but also key. My life is far more settled now, I've gotten a handle on scheduling myself and my life to fit the way my life works right now. I gain more experiences and practice every day. I've had the time to experience and try the things on the rest of my list.
2) Taking care of myself. I made myself sit down and figure out what I needed to do to help myself feel better physically, so that I'd be in the best shape to handle this "whole new world". I tried different sleeping times and schedules until I found one that allowed me to get 7+ hours of sleep on the average night (Yup. I know some of my coworkers talk about getting about 4 hours between shifts. That is not for me. I simply can't do it, and know that I can't. I do not "beat" myself up about it, just work my life to accomodate what I know I need.). I do not routinely "switch over" to a day schedule, as I find that incredibly hard on my body. I also have been very limited on picking up extra time. When specifically asked to come in or stay, I've definitely done it if I've felt able to do so, but I haven't specifically signed up for many extra shifts. I value my time away from work just as much as my time in work, and tried to make a point to have a separation between them, especially this early on when burnout and being overwhelmed is so risky.
I did what I could to prepare meals ahead of time and freeze them, or portion out salad materials, fruit, snacks, etc. I had an "emergency" pair of scrubs on hand in case I realized at the last minute I hadn't done the laundry recently. Little things that made me feel more "in-control" of my life.
3) Having people to talk to. Just knowing that I wasn't alone in my feelings and experiences was wonderful. Talking to both fellow new grads and experieneced nurses that I've worked with has been invaluable. Having someone who will understand my feelings of frustration with certain situations, having someone to bounce concerns and ideas off of, etc. Having someone to double check something in an assessment that I was worried about (For example, I still sometimes ask someone to listen to a murmur and talk me through what I'm hearing and seeing about a baby with one). The glory of my NICU environment is that although I have my own assignment, I'm never really alone. I've got fellow nurses, the charge nurse, practitioners, etc there to help out.
4) Take advantage of opportunities. Our CNSs are wonderful. They make time to talk to us, answer questions, find out information, teach... When I had concerns about my charting, the CNS went though some of my charting with me, gave me pointers, gave me a "rough outline" she'd made up a few years ago for "typical" charting as well as "atypical" charting, etc. I've taken classes that were offered, picked up assignments that allowed me to learn and practice areas of care (all with resources nearby, of course), and gone to inservices and a conference to help gain experience and learn new information. These opportunities can be hard to find if you don't have much available at night, but that depends on your unit.
I'm also finding myself very willing to "float" to our well-newborn and special-care nurseries. Again, I feel better the more experiences I have and the more opportunities to learn that I have. The more I work in the other areas, the better and more comfortable I feel about floating, instead of seeing it as a "bad" experience, the way I know some people do (some really dread floating because of being a "fish out of water" in the other area).
5) Learn, learn, learn. If you feel concerned about assessment skills, and your charge nurse or fellow nurses are responsive, you can mention "I need experience in ____" and if they run across such an experience and have time, they can offer it to you. I've had nurses say, "Hey, want more experience changing lines?" or "Wanna hear a great murmur?" or "Want to observe a post-op assessment?" I bought the nursing handbook of neonatal care book and bring it in to work with me. It's always great to refresh myself in something or look deeper into what going on with a baby I have questions about.
6) When all else fails, make a plan or look for ways to adjust things in the future. I had a very rough time working 5 8-hour nights each week and every other weekend, I felt like I was either always at work, or always getting ready for work, and the only time I had two days off in a row was my weekend. After a few months a 2 12-hour shifts and 2 8-hours shifts each week and every 3rd weekend position opened up (still nights) and I jumped at it. Since then I've had much more flexibility (that extra day off really does make a difference) with my schedule and am finding time to do "stuff" that I'd missed, like seeing friends, making needed appointments, and am considering taking a "fun" class during the summer or fall (bellydancing maybe? Or photography). So I'm beginning to find a nice balance between work, required "life stuff", and fun.
I still have a looooooooooong way to go, and am reminded of that frequently, but I've found a "path" that works for me so far, and it's made me a much different person now than I was 4 or 6 months ago. I feel more confidant in my own skills, fledgling though they may be, as well as my ability to discern when something extends beyond my skills and I need to ask for help. One preceptor once said to me that asking for help is not a sign of weakness or poor nursing skill. Not asking for help when needed is. Took me a little while to find my voice and confidance in speaking up, but now after realizing that most of my coworkers are very open to teaching and helping and won't act negatively towards my questions... well, it's a good feeling :)
I know our situations are different. We likely have different responsibilities, different demands on our time and attentions, and different needs. Things that work for me may not work for you, and things that make a huge difference for you, I may never have thought of. But basically, what I wanted to say when I set out on this incredibly long-winded and likely boring (sorry!) post, is this:
You are not alone in your feelings. Your feelings are IMPORTANT, and nothing to be ashamed about - I would definitely NOT call you a whiner. It's far better to recognize challenges and feelings, as you obviously have done, than try to ignore and let them grow and grow. You are important - your health, your emotions, and your value as a nurse. And so I hope that you can have the support you need to succeed - however you need to :)
If I haven't scared you off with my ridiculously long post, do feel free to PM me if you have any questions or want an ear to talk to :)