Hey volunteer pioneer--
I know it seems like things will always be this hectic and crazy, but don't worry--it will get better!! I'm reaching the end of my first year, and it is crazy to think of how far I've come (and how far I have to go haha). But that crazy, blurred, overwhelmed feeling you're having right now is totally normal. Just take a deep breath and take one shift at a time. You will make mistakes, have hard schedules and tough patients but all of these experiences will help you grow into a better nurse. After a few months, you will become used to the pattern of the shift and the specifics of the floor. It takes time but it will happen.
During a meeting a month into my job for all the new grads, a nurse manager came to talk and introduce herself. At one point she said "you may be wondering at this point why we hired you-because you feel like you're doing everything wrong" I sat there and started nodding because that's exactly how I did feel--then I looked around the room and saw so was everyone else.
As for the cliquey staff-it's common in some places but don't let it get to you. Remember you are a new member of the team and it will also (again) take time for everyone to get to know you. And the best advice I got from someone else is to understand that not everyone will like you! I had a tough time with that the first few months because I was taking it personally. Later I found that the nurses who seemed unfriendly warmed up after I proved myself. Best advice on this front: smile a lot, help out when you can, and take time to make friends on the floor.
Last but not least, try to relax on your days off. Whatever helps you to chill and be happy--do it. The best part about working is there is no homework (unless you're taking side classes...but it's different than school)
Take a deep breath and focus on the present, you can and will get there!!