feeling like a failure as an Rn.

I am an Rn from the Midwest, who works in a small Birthing center. I have been an Rn now for about 14 mos. Recently I am now working in Labor and Delivery on the day shift. (I had to leave my comfort side of postpartum). I feel pretty confident with my relationships I develop with my patients. I often get compliments of how wonderful of a nurse I am...I am just so frustrated in my skills and lack of confidence. I often feel like a failure. I haven't made any mistakes or have been written up yet (by the grace of god) but its very frustrating when these orientees are catching on quicker than I did. Being a new nurse, its hard to vent to others especially when you know that everyone else will know by the time you come back to work. I have just completed my 3rd night of night shift with very little sleep. My lack of confidence is even greater after I had problematic patients after another. I couldn't start my Iv,blood draws, get my foley in, or even find a damn cervix...all in one night. What is even worse is when you finally get accepted by the others on another shift....you now how to prove yourself all over again to another shift (since I am going to noc shift now) What a first impression for my crew on night shift.... I feel like that poor slow turtle who could never reach the finish line.