I feel for you. I graduated at the top of my class only to discover I really didn't know anything at all (at least it felt that way at first!). I was terrified at first as well - I used to say a little silent prayer on my way to work every day that I didn't kill someone today. I learned that fear can be a very good thing for a new nurse - it keeps you from bailing into a situation that you're not ready for. Don't be afraid to ask questions, it's really important to be sure of what you're doing. At the same time, don't be afraid to question what someone else might ask of you or tell you to do. You do have a mind and an education. If your gut is telling you something is wrong, it most likely is. At the end of the day, it's your name on the care records.
I was thinking back to my first day "on the floor" and had to LOL! With a preceptor, I was caring for a cancer pt who happened to have a rectal tube inserted. I remembered talking about them in school, what the function was, etc., but I had no idea they were inserted so far into the body! The pt requested that it be removed, so, with the pt lying on their side facing ME, and my preceptor on the opposite side of the bed facing, well, not the pts face
, I proceeded to remove it. Not realizing how long it was, I failed to contain it in my hand as I removed it, causing it to sort of "whip" out and spray my preceptor with liquid stool! Needless to say, I was mortified, and pretty sure that spraying your preceptor with stool was not a good first impression. The only question she had was "Is it in my hair?". When she knew that it had only doused her nicely pressed uniform, she moved right on to the next thing, no problem. Just another day at work. Believe me, it took a while, but now the story just makes me laugh.
Hang in there, and keep a sense of humor. Some days you'll have to either laugh or cry... try to laugh!