Does it ever make you nervous?

I think all of us- student or licensed nurse- go to work thinking, "I hope I don't hurt anyone today." The fear may not be that we give the wrong patient orange juice, but that we program the wrong drip rate, miss an important clinical sign of a change in condition, inadvertently contaminate a sterile field, etc. It's a normal concern, in our profession. This fear is what drives you to be cautious. To read orders carefully, to check (and recheck) your dosage calculations, to look up diagnoses and medications you don't know well, to ask a seasoned nurse before you perform an intervention. The worry you describe is not only normal, it's healthy.