Question about a nursing career

I am currently going to college for nursing. I have alot of medical professions in my family and health care fascinates me. However, I used to work as a ward clerk in a small hospital when I was younger (18)and as a ward clerk it was my job to send the order for labwork, that the docter had ordered, down to the lab. This particular day the docter had ordered blood cultures on a patient and I misread the order and ordered a blood type and cross. This was for an ICU patient. The blood arrived and if it weren't for the nurse that caught my mistake, I probably could have killed that patient. This situation haunts me even to this day ( i'm 26 now) and I am scared to death I'm going to hurt someone if I become a nurse. Even though I desire very much to be able to help people, I get that strong fear that I'm to stupid to be in such a serious field. I have a strong fear of making some big mistake my first day and really hurting someone. Do you believe this is a rational fear and maybe I shouldn't be getting into the nursing profession?
I can completely understand your fear. Keep in mind...you were 18 and a lot of maturity happens once you progress though college. I believe you are right where you belong. The most important part of this mistake it what you learned from it. As you know all blood orders etc are checked by at least 2 nurses. Hang in there! Trust your instincts...there are almost always right!
Health care has a lot of 'checks and balances' that keep patients safe. We know that human error is a fact of life - it's going to happen. So we minimize situations that have been known to increase human error. We are moving toward electronic charting and CPOE to prevent errors due to inability to read/interpret handwriting. We have automated pharmacy systems that detect conflicting orders, potential drug interactions or known allergies. We are implementing bedside medication verification to minimize drug errors in administration. We have established "time outs" and numerous other safeguards to prevent surgical errors . . . and the list gets longer every day.But the most important safeguard we have is the willingness of healthcare professionals and caregivers to react quickly and appropriately when they spot a potential error. I honestly believe that the US healthcare system is the safest in the world and we will only get better. Don't let your fear keep you from a potentially rewarding career.
thanks to both of you for your responses, they make me feel better . How do you handle situations where there isn't time for all those checks and rechecks? For instance if someone comes into the ER and you think they're fine one minute and then all of a sudden they start having a heart attack. Does the adrenyln pumping, feel like your own hearts gonna stop feeling go away with knowledge on how to handle that situation? Or will I always react that way? My mother was a doctor and I spent alot of time in the hospital visiting her and I was there for one of those kinds of situations and that's how it felt, to me. I of couse was hustled out of the way but I saw the gaggle of nurses rushing in their and my mom rushing in their and people were yelling and running around really fast. I worry about being in that kind of situation and doing something wrong.