Shavsa, everyone here has given you excellent advice, especially asking the older nurses for their opinions. Do not EVER ask them to do your work, unless there is an emergency. Any time you have a moment, offer to lend a hand, but don't let yourself be a doormat. Avail yourself of any opportunity to learn, even if it means coming in and not getting paid for it. Show folks that you are willing to learn, that you listen when they speak, and that you are a diligent nurse who cares about her patients. Get to know the physicians, and talk with the ones who are willing to teach about your patients. Not chitchat mind you, and not in a way to make them think you are questioning their expertise, but in way that makes them know that you are interested in learning more, as a health professional. You would be amazed at what they are willing to share. Before you become involved in any conversation with anyone, though, be sure that those meds are passed, vitals taken, shift assessments are done, piggybacks hung, anybody fed that isn't a self-feed, dressings are changed, foleys are emptied, I &0's are up to date, beds and baths are done, Accu cheks done (and charted) and that your charting is pretty much up to date.
Try not to get in the habit of waiting for other people to answer your call lights, spending too much time on the phone, and asking too many favors, unless you have an emergent patient. Most everybody is willing to help a nurse who is getting overrun, if it is an occasional thing. A nurse who is always behind needs to pull back and reassess her priorities and how she allots her time. If you need help with that, ask someone that you respect, and who always seems to have things done.
Do not be dissuaded because your Supervisor seems to be riding you. Perhaps she has seen too many new nurses who just can't get it together, and she doesn't want you to be one of them. On the other hand, she just might be a cranky person, and nothing will please her. Try to watch to see how she does with other folks. If she is cranky with everyone, then it is her personality. If she picks favorites, watch out. My ADN clinical instructor was considered a Hitler, but it was because she insisted that we do things right, to the letter-she didn't let anything slide. It wasn't because she was a mean person. Actually, she was quite tender-hearted, but when it came to students, we toed the line! Her rational was that she was not going to approve of a mediocre way to do anything! It was possible to get an A from her-I did it, in two clinical rotations.
Last, don't worry about being upset and crying at the end of the evening. You have to let yourself vent, and if you are thinking about your job on your way home and at home, then you really ARE a good nurse. You are using the nursing process, of identifying a problem, proposing and implementing a solution, and evaluating the result of what you've done. It also indicates that you have embraced nursing as a PROFESSION, not a job. Best wishes to you. Things will get better, and one day, new nurses will be looking to you for advice and assistance!