first of all, WELCOME to the BB ! I'm glad you found us, and I'm sure you will receive plenty of support here.
You are certainly not alone in your anxiety.. I know LOTS of nurses who have felt less than confident in their abilities, and all will tell you that this will pass. It is a GOOD thing that you doublecheck, and are conscientious ! Try to not DWELL on what you might not be doing, however. Go over your mental checklist, or even a written one and cross things out as you accomplish them, but don't DWELL on the negative thoughts.. they will pull you under.
The more you dwell on the negative, the more anxious you will become, and the less confident in yourself. Negativity breeds negativity. If you believe your concerns are VALID, seek advice/guidance/feedback from your colleagues or charge nurse. If you just THINK you're not doing as well as you feel you should be, then keep a list of all things you have accomplished and done properly each day..look at yourself in the mirror each day and tell yourself OUT LOUD " Stella, you're a darn good nurse !" and then smile at yourself. Sound silly? Perhaps. But you know what? You become what you THINK ! And what you HEAR.
So think positive, and seek reinforcement, and leave each day knowing that you have done your very best and given your all... and feel GOOD about it !
Hang in there !