Ahhhh....I remember those days. I can totally relate to how you are feeling. I know it's tough, and it may seem like your preceptor is not making it any easier, but she honestly probably is just trying to toughen you up by giving you some tough love. Nonetheless, it would benefit you to learn from someone you feel comfortable with, someone who you feel isn't gonna snap if you miss that IV start. Maybe talk to her first and tell her how you feel. If she doesn't improve then go to the supervisor. The way you're feeling is TOTALLY NORMAL. I've worked ER for about 5 years now, and I remember how I used to dread going into work everyday for the first year. I would ask myself "Why the heck am I doing this?" I would have this nervousness in the pit of my stomach from the beginning of my work day till the end.
Then finally, I remember driving to work and not being scared anymore. It was an AHA moment for me. They say the first year of nursing is the hardest, and it must be true because 1/5 of nurses quit after their first year. I don't think the issue is you at all. I think that the first year is just HARD PERIOD. In ER, you see it all. You see oncology patient's, L&D patient's, PEDS, geriatrics, and mental health patients. It's a stressful specialty in the sense that you can't really plan your day. You get whatever walks through that door and you have to play CSI and try to anticipate what's going on with the patient, then stablilize them. I still have shifts where everything goes wrong, and I seriously just want to no show the next day. I admit though, I have fewer of them, and you will too.
Keep your head up! Don't feel dumb because you don't know it all. You sound like a very motivated individual who is just trying their best to do the job right. Cry and let it out after you've had a Jerry Springer shift, but then don't take the stress of work with you. Leave it at work. Know that this feeling will pass with time. Whatever you do, DON'T SACRIFICE SAFETY FOR SPEED. Do what feels right, and when in doubt, DOUBLE CHECK, TRIPLE CHECK AND ASK!
Hope this helps :nuke: