If you are only 2 weeks into your orientation, then as a new grad (ideally) you should still be receiving quite a lot of support and assistance from your preceptor. Do you have a consistent preceptor that you feel comfortable talking to? Are you receiving feedback? Does your nurse educator meet with you to ask how things are going and what you are learning?
I've been a nurse for 11 years, and have been precepting for about 8 of them. I want to say first of all that being nervous is completely normal. I still remember being absolutely terrified when I started my first job (on a very busy post-op unit whose patients had tubes coming out of every bodily orifice). I actually worry if my orientee has an apparent complete lack of nerves or doesn't call me with questions and/or to come check that they "set an infusion up right" before starting it. I tend to follow those orientees a bit closer, go in behind them in rooms to check their work, etc. because it is *normal* to want your preceptor to check after you for the first 2-3 weeks. Its normal to ask her questions your entire orientation (which will ideally be at least 10 weeks). It's normal to still have questions after you finish orientation (especially during the first 6 months). Being a nurse is serious business, and even now, even after 11 years, I triple check my work and bounce questions off my co-workers if I am doing something I haven't done in a while.
That said, your confidence should slowly increase over the next few weeks. If, after the half way point of your orientation you are still feeling mind-numbing fear, talk to your preceptor, and/or talk to your nurse educator. In the meantime take full advantage of the safety features that are in place for med administration. Follow your 5 rights to a T, use bar code scanning, guardrails on your IV pumps, 2nd nurse verification for high risk meds, and any other best practice safety checks that your hospital uses. We are all human, and those features are in place to protect us and the patients. Best of luck!!