You will. Give yourself credit for the things you do know.
I've been in the OR for 3 months now. I have days when I think WOW! This is a piece of cake, I love my job!
Then there are days when someone asks my for something and while fighting to suppress my "dear in the headlights" look I think why the heck did I switch to the OR.
Now I take time each day, usually on my drive home, to think about that things I got right that day and ask myself if I could have done those things the week or month before. This helps me with the "will I ever get it?" feelings.
Whatever you do don't compare yourself to your coworkers who have been in the OR for 2, 5, 10 or 40 years. I used to do this all the time and it really discouraged me. One day the hospital had a skills fair for all the nurses. I had to help a bunch of my coworkers on some of the more bedside oriented skills. Lets just say they were challenged when it came to things like the assessment and care of pressure sores. At that moment I realized there were lots of things I knew that my very experience OR nurses didn't know. That seemed to change my feelings of being "dumb" to "hey, I've only been doing this 3 months. When I get to 2 years I'll be at least as good as them".
I respect and admire my coworkers for their skills and dedication (well, 99% of them). If you haven't already have them share with you their experiences as new nurses in the OR. You'll be amazed how similar some of their experiences and feelings will be with yours.
Good luck and keep your chin up!